Do you only have a small amount of rhubarb? Or do you only want to make a small rhubarb crisp? Or maybe you don't want to heat up your house, making rhubarb crisp? OR you simply just need an easy rhubarb crisp STAT!? If you said "YES!" to any of these statements, then this is your Rhubarb Crisp recipe! This Microwave Rhubarb Crisp (in a Mug) is quick and easy to make in the microwave and perfect for 1-2 servings.
This individual rhubarb crisp is an easy dessert made with a small amount of rhubarb and cooked in a mug in the microwave! This recipe is popular during rhubarb season (April until July), but great any time of year (made with frozen rhubarb). It was inspired by my Healthy Apple Crisp in a Mug on this site, and inspired my Old-Fashioned Rhubarb Crumble! If you're looking for recipes for rhubarb crisp or for using up a small amount of rhubarb, you'll love this version! It's a quick and delicious way to get your rhubarb crisp fix.
🍒Reader Review
"Tried this with our first 4-5 stalks of spring. It was so easy and incredibly delicious!
Ed in Wisconsin
Ps. Didn't have any quick oatmeal, so used packet of flavored instant and mixed with butter for topping and it turned out great!" ⭐⭐⭐⭐⭐
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If you don't grow your own rhubarb, you can often find it at the grocery store or at a Farmer's Market during rhubarb season.
🥘Ingredient Notes
This easy rhubarb crisp recipe has quite a bit of sugar to balance out the tart rhubarb, but you can reduce it to your liking or use a sugar substitute, if you prefer.
For this microwave crisp recipe, you'll need:
- Fresh rhubarb (or frozen rhubarb). Both fresh and frozen rhubarb work well with this recipe. If using frozen, defrost and drain the rhubarb before you measure.
- Quick rolled oats. Quick rolled oats or "quick oats" cook faster than regular rolled oats, so that's why I use them in this recipe. I don't recommend using instant oats, although one reader tried it and said it turned out great!
- Unsalted Butter. I prefer to use unsalted butter in my recipes so I can control the salt. The salt in content in salted butter varies from brand to brand.
- Orange zest. Orange zest pairs exceptionally well with the rhubarb, elevating the flavor.
*See recipe card for full list of ingredients and quantities
📖Variations & Substitutions
- WW friendly - use a light butter or margarine and a sugar substitute (like Monk fruit- but only use ½ the indicated amount for sugar)
- Dairy-free - use vegan margarine ( I use Becel)
🔪Step-by-Step: How to Make Rhubarb Crisp in the Microwave
Cooking rhubarb in the microwave is quick and easy!
Filling: Toss chopped rhubarb with brown sugar, white sugar, orange zest, vanilla extract, cinnamon, and flour.
Take a microwave-safe mug and fill it with the rhubarb mixture.
Topping: In a small bowl, combine flour, quick oats, brown sugar, white sugar, and cinnamon. Cut the butter in to create the crisp topping (or see top tip in post for grating frozen butter)
Spoon the crisp topping over the rhubarb mixture. Place in the microwave oven and cook on high for about 2 ½ minutes or until the butter is melted into the topping. *Cooking time is based on my 1200W microwave, so your timing might vary between 2-3 minutes.
Hint: Carefully remove from the microwave (I use an oven mitt) and let stand until cool enough to eat. Be careful because it's going to be really hot at first! When it has cooled a little, mix it together for the best taste results, then add the whipped cream or a scoop of ice cream, cinnamon, and orange zest garnish (optional)
Expert Recipe Tips
- Microwave power matters. Microwave wattages vary-if yours is lower than 1200W, start with 3 minutes and adjust as needed. If it's higher, start with 2 minutes and check to avoid overcooking.
- Use a tall or wider mug to prevent overflow. Choose a mug that's at least 12-14 oz to give the crisp room to rise and bubble without spilling over.
- Balance the sweetness. Taste a small piece of your rhubarb before making the recipe. If it's particularly sweet or mild, you can slightly reduce the sugar. Tart rhubarb needs the full amount for best balance.
- Add texture with nuts. For added crunch, stir in 1 teaspoon of chopped pecans or almonds into the topping mixture before microwaving.
- Microwave-safe whipped topping tip. If you're using store-bought canned whipped cream, wait until the crisp has cooled slightly before adding it. Otherwise, it will melt too quickly.
- Prevent a rubbery topping. Avoid overmixing the topping-cut in the butter just until crumbly. Overworking it can lead to a dense, rubbery texture after microwaving.
- Let it rest for best flavor. Letting the crisp cool for 5 minutes enhances the flavor and allows the filling to thicken slightly, giving you the best texture.
🍽Equipment
For this individual rhubarb crisp, you'll need a microwave safe mug, a zester, pastry cutter (or use a cheese grater -see my Top Tip below) (affiliate links)
🌡️Storage
Store this recipe for rhubarb microwave crisp for one in an airtight container in the fridge for up to 3 days. Alternatively, once the mug has completely cooled, cover it in plastic wrap and store it right in the mug, in the fridge. You can also freeze it in a sealed container for up to 3 months.
👪 Serving Size
This is a single-serving rhubarb crisp, so it makes 1 large serving. 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'll just need a larger mug (I doubled the recipe for the very large mug in the photos) or additional mugs and additional cooking time. You can serve this easy rhubarb crisp in a mug or in a dessert dish!
Top tips
Frozen Rhubarb: If you are making rhubarb crisp with frozen rhubarb, it's really important to completely defrost and drain the rhubarb first, then measure. It shrinks in the freezing process. *Don't measure it frozen
Keep your butter in the freezer and grate it into the crisp - it's so much easier and less messy!
❔ Recipe FAQ's
Microwaves don't brown food like ovens do, so the texture won't be as crisp as a baked version. For a firmer topping, try microwaving uncovered for longer intervals (in 15-second bursts after the initial cooking) or use a slightly wider, shallow mug for better surface area.
Yes! Just make sure the container is microwave-safe and has enough room to prevent bubbling over. Ramekins work well and offer a nice presentation.
The butter should be fully melted into the topping, and the filling should be bubbling around the edges. If not, continue cooking in 15-second increments, watching closely.
You can assemble the crisp (filling and topping) and store it in the fridge for up to 24 hours before microwaving. Be sure to use a container that's safe for both fridge and microwave.
There is no sacrificing taste with making Rhubarb Crisp in the microwave! The only difference is that you save time and don't heat up your house. Plus, you have a delicious single serving of rhubarb crisp in only a few minutes. So if you are looking for quick and easy recipes for rhubarb crisp to savor the taste of summer, you'll love this one!
And if you love fruit crisps and crumbles, give my Mixed Berry Crumble (with Lemon, Mint & Coconut) a try!
📋More Rhubarb Recipes
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📋 Microwave Rhubarb Crisp (in a mug)
Ingredients
Filling
- ¾ cup rhubarb (fresh or frozen) * if using frozen, see Top Tips
- ½ teaspoon vanilla
- 2 tablespoon white granulated sugar
- 1 tablespoon brown sugar
- ¼ teaspoon orange zest
- ½ teaspoon cinnamon
- 1 tablespoon all-purpose flour
Topping
- 3 tablespoon quick rolled oats
- 1 tablespoon all purpose flour
- 1 tablespoon brown sugar
- ½ tablespoon white granulated sugar
- ½ teaspoon cinnamon
- 1 tablespoon unsalted butter (cold or frozen - see top tips)
Garnish
- 2 light whipped cream * I use light real whipped cream (spray bottle)
- cinnamon
Instructions
Filling:
- Toss chopped rhubarb with brown sugar, white sugar, orange zest, vanilla extract, cinnamon and flour.¾ cup rhubarb (fresh or frozen), ½ teaspoon vanilla, 2 tablespoon white granulated sugar, 1 tablespoon brown sugar, ¼ teaspoon orange zest, ½ teaspoon cinnamon, 1 tablespoon all-purpose flour
- Take a microwave safe mug and fill it with the rhubarb filling.
Topping:
- In a small bowl stir in the rolled oats, flour, brown sugar, white sugar and cinnamon. Cut the cold butter in with a pastry blender to create the crisp topping (or see top tip in post for grating frozen butter)3 tablespoon quick rolled oats, 1 tablespoon all purpose flour, 1 tablespoon brown sugar, ½ tablespoon white granulated sugar, ½ teaspoon cinnamon, 1 tablespoon unsalted butter
- Spoon the crisp mixture over the top of the fruit filling. Microwave for about- 2 ½ minutes or until the butter is melted into the topping. Cooking time is based on my 1200W microwave so your timing might vary between 2-3 minutes.
- Carefully remove from the microwave (I use an oven mitt) and let stand until cool enough to eat. Be careful because it's going to be really hot at first!
Garnish
- Enjoy warm or cold with whipped cream or a big scoop of vanilla ice cream and a sprinkle of cinnamon and additional orange zest.2 light whipped cream, cinnamon
Notes
-
- Microwave power matters. Microwave wattages vary-if yours is lower than 1200W, start with 3 minutes and adjust as needed. If it's higher, start with 2 minutes and check to avoid overcooking.
-
- Use a tall or wider mug to prevent overflow. Choose a mug that's at least 12-14 oz to give the crisp room to rise and bubble without spilling over.
-
- Balance the sweetness. Taste a small piece of your rhubarb before making the recipe. If it's particularly sweet or mild, you can slightly reduce the sugar. Tart rhubarb needs the full amount for best balance.
-
- Add texture with nuts. For added crunch, stir in 1 teaspoon of chopped pecans or almonds into the topping mixture before microwaving.
-
- Microwave-safe whipped topping tip. If you're using store-bought canned whipped cream, wait until the crisp has cooled slightly before adding it. Otherwise, it will melt too quickly.
-
- Prevent a rubbery topping. Avoid overmixing the topping-cut in the butter just until crumbly. Overworking it can lead to a dense, rubbery texture after microwaving.
-
- Let it rest for best flavor. Letting the crisp cool for 5 minutes enhances the flavor.
Linda ILG
Delicious & very easy to make, even with gluten free oats & gluten free oat flour, with a touch of xanthin gum! 👍👍
Terri Gilson
Hi Linda,
So glad you loved it and were able to make the crisp gluten -free!
Terri
Ed
Tried this with our first 4-5 stalks of spring. It was so easy and incredibly delicious!
Ed in Wisconsin
Ps. Didn’t have any quick oatmeal, so used packet of flavored instant and mixed with butter for topping and it turned out great.
Terri Gilson
Hi Ed,
I'm so glad you enjoyed it! Glad to hear that you were able to improvise with the oatmeal too 🙂
Terri
Asha
Such a cute little mug of rhubarb deliciousness. Love how easy and quick this is to make! And the portion size is perfect for someone who lives alone.
Shelby
Anything in a mug is a huge win for me and the crumble topping on this was probably my favorite part hehe. Glad it's a mini serving!
Bernice
Ooooh this is DANGEROUSLY good. With just the two of us in the house, I didn't want to make an entire rhubarb crisp. Now I can and we don't have to eat a giant pan of it!
Terri Gilson
I know, Bernice! I can't make it too often 🙂
nancy
lovely!! how perfect is this to be made in the microwave! the flavour combo was great and not too sweet!