This root beer float cake recipe tastes just like a root beer float, but even better because it's a cake! And it's the ultimate happy birthday cake. Layers of chocolate cake, flavored with root beer extract, then painted in root beer syrup, making it super moist, with a light, fluffy, and not too sweet shortening (Crisco) based icing. The root beer cake is topped with marshmallow fluff to look like melted ice cream, with a cherry on top! If you are looking for summer cakes or a birthday cake recipes, this is your cake!
Preheat oven to 350 degrees F/175 degrees C. Prepare (I use Wilton Cake release https://amzn.to/3mh24FK -affiliate link) three 8 inch cake pans and set aside.
In the bowl of a stand mixer (with paddle attachment), combine flour, white granulated sugar, cocoa powder, baking powder, baking soda, and salt.1 ¾ cup all purpose flour
Add eggs, milk, oil and root beer extract to the flour mixture. Beat on medium speed for 2 minutes. Slowly stir in boiling water and continue mixing for another minute or until combined. 2 large eggs1 cup boiling water
Pour cake batter evenly  into 3- 8 inch prepared cake pans until each cake pan is ⅔ full. **Batter will be runny
Bake cake for about 30 minutes or until center of tops spring back when lightly touched. Let cakes cool for 10 minutes before removing from pans to finish cooling onto a wire rack
While cakes cool, boil root beer in a heavy sauce pan until reduced by half. It will form a syrupy liquid. Brush warm cakes with this root beer concentrate and let finish cooling. 1 cup root beer sodaOnce cool, cover in plastic wrap and refrigerate for several hours or overnight. **this is not critical, but you do get the best results if you do this
Whipped Cream Buttercream:
Part 1:
Put shortening in bowl of stand mixer and gradually add powdered sugar. Beat about 5 minutes until mixture is very creamy and fluffy. Set this aside.2 ½ cups shortening
Part 2:
In a very clean large bowl mix dry ingredients (sugar salt and meringue powder). Add BOILING water and immediately mix on high speed. Beat until stiff peaks form, about 8 minutes. When mixture begins to get stiff add root beer extract. ¾ cup white granulated sugar2 TBS root beer extract
Combine both mixtures and beat together for another 8 minutes. When finished, use a rubber spatula to down beat a little to remove some of the air bubbles. Frosting will be very light and creamy. Add brown food coloring if you desire. Cover. DO NOT REFRIGERATE.1-2 teaspoon Brown gel colouring
The frosting may be kept at room temperature for 1 month. Whip with a spoon each time you use it to restore fluffiness. * Makes enough to ice this 3 layer 8 inch cakeÂ
Assembly & Garnish:
Transfer cakes to a cake plate. Fill and frost the cake layers then run a comb along the sides of the cake. (see sample method in video). Pipe a border with a #21 icing tip (optional).
Add the marshmallow fluff, then a maraschino cherry in the centre and sprinkle with chocolate sprinkles.2-3 tablespoon marshmallow fluff/marshmallow creme
Serve with vanilla ice cream, if desired.
Notes
*See post contents for important recipe information and tips!
Nutrition Facts
🎂 Root Beer Float Layer Cake Recipe
Amount Per Serving (1 slice)
Calories 758Calories from Fat 414
% Daily Value*
Fat 46g71%
Saturated Fat 10g63%
Trans Fat 5g
Polyunsaturated Fat 13g
Monounsaturated Fat 21g
Cholesterol 24mg8%
Sodium 347mg15%
Potassium 171mg5%
Carbohydrates 88g29%
Fiber 2g8%
Sugar 73g81%
Protein 4g8%
Vitamin A 70IU1%
Calcium 56mg6%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.