This recipe was a labour of love! I wanted to create a baked rhubarb oatmeal that was portable and perfect for on-the-go! This Rhubarb Baked Oatmeal is the ultimate "The Lazy Way" breakfast. After several kitchen trials to solve the "mushy oatmeal" problem, I've perfected a sturdy, portable square that has the tender crumb of a rhubarb muffin but is made in one easy pan. And it's by far one of the most delicious recipes I've ever created!

This Rhubarb Oatmeal is popular in the spring, during rhubarb season, but is great anytime of year using frozen rhubarb. Whether you are looking for a healthy grab-and-go breakfast for busy work mornings or a spectacular addition to a spring brunch potluck, these handheld bars are a guaranteed win. It was inspired by my Rhubarb Coffee Cake and my Rhubarb Overnight Oats.
Recipe Overview: Rhubarb Baked Oatmeal
- Ready In: 55 Minutes
- Serves: 12 servings
- Calories: 195 kcal per serving
- Main Ingredients: Quick oats, rhubarb, applesauce, orange juice, brown sugar, and coconut.
- Dietary Info: Vegetarian, High-fiber.
- Weight Watchers Points: 5 WW points per square.
- Difficulty: Easy.
- Why You'll Love It: It's a "muffin-in-a-pan" hack! You get the portability of a breakfast bar with the moist, jammy texture of a gourmet baked good. It's budget-friendly, meal-prep ready, and uses a "surface sweetness" trick to keep it healthy, while tasting like a treat.
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- 🥘Ingredient Notes
- 📖 Variations & Substitutions
- 🔪How to Make Baked Rhubarb Oatmeal
- Expert Recipe Tips
- 🥗 Pairing
- 🌡️Storage
- 👪 Serving Size
- 🔢WW Points
- ❔Recipe FAQs
- Didn't find the answer you're looking for?
- More Rhubarb Recipes
- Rhubarb Baked Oatmeal (Transportable) Recipe
Looking for more rhubarb breakfast or brunch recipes? Check out these 15 Rhubarb Breakfast Recipes!
🥘Ingredient Notes

- Quick Oats: I use quick oats for this version to get a tighter, more cake-like crumb that holds together for transport. *Don't use 'instant oats' or it will turn to mush!
- Rhubarb: Dicing the internal rhubarb small is the secret to ensuring it melts into the batter without creating soggy pockets.
- Applesauce & Orange Juice: These provide natural moisture and a depth of flavor without needing excessive butter or oil.
- The Topping Mix: Using a blend of brown and white sugar specifically on the rhubarb pieces creates a jammy, professional glaze.
*Please see recipe card for full list of ingredients or quantities.
📖 Variations & Substitutions
- Gluten-Free: Use certified gluten-free oats and swap the all-purpose flour for a 1:1 gluten-free flour blend or oat flour.
- Dairy-Free: Use almond, soy, or oat milk in place of 1% milk.
- Nut-Free: Simply omit the slivered almonds on top.
- Fruit Swaps: If rhubarb isn't in season, this base works spectacularly with cranberries or tart Granny Smith apples.
🔪How to Make Baked Rhubarb Oatmeal
PREP: Preheat oven to 350° F/176° C. Lightly spray an 8x8 baking dish with non-stick spray.

- Step 1: Mix dry ingredients together in a large bowl (oats, flour, chia, brown sugar, baking powder, salt, cinnamon, and coconut.

- Step 2: Whisk together milk, applesauce, butter, vanilla extract, orange juice, orange zest, and egg in a separate bowl.

- Step 3: Add milk mixture to oat mixture. Stir in chopped rhubarb. Stir until combined. *Allow to stand for 10 minutes.

- Step 4: Pour into prepared pan.

- Step 5: Add remaining pieces of chopped rhubarb, pushing them slightly into the oats.

- Step 6: Mix topping ingredients together (cinnamon, brown sugar, and white sugar).

- Step 7: Sprinkle on the almonds, then the sugar-cinnamon mixture, ensuring you get most of the topping on the pieces of rhubarb.

- Step 8: Bake 35-45 minutes (I needed the entire 45 minutes) in a preheated oven. It's done when the center is set, and a cake tester comes out clean. Allow to cool for a full 20 minutes before removing, using an offset spatula to loosen. Garnish with additional sweetened coconut flakes.

Expert Recipe Tips
- Better the Next Day! While these squares are delicious warm, they actually taste even sweeter after a rest in the fridge! Chilling allows the tart rhubarb juices to meld with the brown sugar and oats, creating a perfectly balanced, jammy flavor, while making the bars sturdier. This makes them the ultimate make-ahead breakfast for busy mornings! If you prefer to eat your baked oatmeal warm and want a little extra sweetness, I recommend a tiny drizzle of maple syrup or sweetened yogurt on top.
- Using Frozen Rhubarb: If you are using frozen rhubarb, do not defrost or drain it! I have carefully balanced this recipe with less milk to account for the natural juices the rhubarb releases as it bakes. Using it straight from the freezer ensures your oats stay moist and flavorful. Just be sure to dice the stalks into small, pea-sized pieces while they are still frozen for the best distribution!
- The Sweetness Balance: You might notice that these squares taste sweeter when cold! Chilling allows the flavors to meld and the tartness of the rhubarb to mellow.
- The 10-Minute Hydration: Don't skip the rest! Letting the batter sit for 10 minutes before baking allows the oats and chia seeds to absorb the liquid. This is the secret to a non-mushy, portable square.
- The "Clean Cut" Rule: Let the pan cool for at least 20 minutes before slicing. For the most professional, sharp edges, chill the bars in the fridge before cutting.
🥗 Pairing
This Rhubarb Oatmeal is perfect for grab-and-go, but it's also ideal for a potluck. If you're having a breakfast spread, you can serve it with Air Fryer Turkey Sausage, Old Fashioned Fruit Salad (with Honey Lime Dressing), or eggs, such as my Roasted Red Pepper Egg White Bites Recipe (shown)or my Maple Sausage Brunch Bites!

🌡️Storage
- Fridge: Store in an airtight container for up to 5 days.
- Freezer: These freeze beautifully! Wrap individual squares in plastic wrap and store in a freezer bag for up to 3 months.
- Reheating: Microwave for 30-45 seconds for a "just-baked" warm feel, or eat them cold as a handheld breakfast bar. If you want them cold, but they are frozen, cook for 15- 20 seconds in the microwave.
👪 Serving Size
This Portable Rhubarb Baked Oatmeal recipe makes 12 servings, depending on how large you cut the pieces. However, you can half, double, or triple the recipe by clicking on the serving number and selecting the number of servings you'd like. The ingredient quantities will automatically adjust. You can also ask AI (under FAQ's) to scale the recipe to a different-sized pan (i.e., 9x13).
🔢WW Points
This recipe is 5 WW points per square (when cut into 12).
- Lighten-Up: You can bring the points down by using a brown sugar substitute (like Monk Fruit) in the batter. You'll only need half the amount of monk fruit (¼ cup). However, I recommend keeping the real sugar for the topping to get that spectacular caramelized glaze!
❔Recipe FAQs
Yes! Do not thaw it first. Simply dice it while frozen and toss it in. You may need an extra 2-3 minutes of bake time to account for the extra moisture.
This usually happens if the 10-minute rest was skipped or if the rhubarb pieces were too large. Ensure you use the ¾ cup milk measurement-it seems low, but the rhubarb releases its own juice as it bakes!
Yes! Because of the cinnamon sugar topping, kids love the jammy sweetness. If you have a real sweet tooth, you can add a tiny drizzle of maple syrup when serving it warm.
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This Portable Rhubarb Baked Oatmeal is proof that you don't have to choose between a healthy breakfast and a convenient one. It solves the mushy oatmeal dilemma once and for all.
Give these jammy, muffin-like squares a try this week! If you love them, please leave a star rating and a comment below-it's the best way to support my kitchen meanderings!
More Rhubarb Recipes
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Rhubarb Baked Oatmeal (Transportable) Recipe
Ingredients
- 2¼ cups quick oats
- ¼ cup all- purpose flour
- 1 teaspoon baking powder
- 1 teaspoon cinnamon.
- ⅛ cup chia seeds
- ⅓ cup sweetened coconut flakes
- ½ cup brown sugar packed
- ¼ teaspoon salt
- ¾ cups Milk *I use 1%
- ½ cup unsweetened applesauce
- ¼ cup orange juice *I use freshly squeezed
- 1 teaspoon orange zest
- 2 large eggs
- 2 tablespoon melted butter * I use unsalted
- 2 teaspoon vanilla extract
- 1 cups rhubarb diced small
Topping
- ¼ cup slivered almonds
- ¼ cup rhubarb pieces
- 1 tbsp brown sugar
- ½ tablespoon white sugar
- ¼ tsp cinnamon
Instructions
- Preheat oven to 350° F176° C . Lightly spray an 8x8 baking dish with non-stick spray.
- Mix Dry: ingredients together in a large bowl.2¼ cups quick oats, ¼ cup all- purpose flour, 1 teaspoon baking powder, 1 teaspoon cinnamon., ⅛ cup chia seeds, ⅓ cup sweetened coconut flakes, ½ cup brown sugar, ¼ teaspoon salt
- Whisk together milk, applesauce, butter, orange juice and orange zest, and egg in a separate bowl.¾ cups Milk , ½ cup unsweetened applesauce, ¼ cup orange juice, 1 teaspoon orange zest, 2 large eggs, 2 tablespoon melted butter, 2 teaspoon vanilla extract
- Add milk mixture to oat mixture. Stir in chopped rhubarb. Stir until combined.1 cups rhubarb
- Allow to stand for 10 minutes.
- Pour into prepared pan.
- Add remaining pieces of chopped rhubarb, pushing them slightly into the oats.¼ cup rhubarb pieces
- Mix topping together in a bowl1 tablespoon brown sugar, ½ tablespoon white sugar, ¼ teaspoon cinnamon
- Sprinkle on slivered almonds and topping. Try to sprinkle the sugar topping directly over the pieces of rhubarb.¼ cup slivered almonds
- Bake 35-44 minutes.
- It's done when the center is set and a cake tester comes out clean.
- Allow to cool for 10 minutes before removing, using an offset spatula to loosen. Serve or store covered in the refrigerator for up to a week. Heat for 15-20 seconds in the microwave. Freeze for up to 3 months.
Notes
- Better the Next Day! While these squares are delicious warm, they actually taste even sweeter after a rest in the fridge! Chilling allows the tart rhubarb juices to meld with the brown sugar and oats, creating a perfectly balanced, jammy flavor, while making the bars sturdier. It makes them the ultimate make-ahead breakfast for busy mornings! If you prefer to eat your baked oatmeal warm and want a little extra sweetness, I recommend a tiny drizzle of maple syrup or sweetened yogurt on top.
- Using Frozen Rhubarb: If you are using frozen rhubarb, do not defrost or drain it! I have carefully balanced this recipe with less milk to account for the natural juices the rhubarb releases as it bakes. Using it straight from the freezer ensures your oats stay moist and flavorful. Just be sure to dice the stalks into small, pea-sized pieces while they are still frozen for the best distribution!
- The Sweetness Balance: You might notice that these squares taste sweeter when cold! Chilling allows the flavors to meld and the tartness of the rhubarb to mellow.
- The 10-Minute Hydration: Don't skip the rest! Letting the batter sit for 10 minutes before baking allows the oats and chia seeds to absorb the liquid. This is the secret to a non-mushy, portable square.
- The "Clean Cut" Rule: Let the pan cool for at least 20 minutes before slicing. For the most professional, sharp edges, chill the bars in the fridge before cutting.
- Fridge: Store in an airtight container for up to 5 days.
- Freezer: These freeze beautifully! Wrap individual squares in plastic wrap and store in a freezer bag for up to 3 months.
- Reheating: Microwave for 30-45 seconds for a "just-baked" warm feel, or eat them cold as a handheld breakfast bar. If you want them cold, but they are frozen, cook for 15- 20 seconds in the microwave.
- Lighten-Up: You can bring the points down by using a brown sugar substitute (like Monk Fruit) in the batter. You'll only need half the amount of monk fruit (¼ cup). However, I recommend keeping the real sugar for the topping to get that spectacular caramelized glaze!








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