This recipe will show you how to make the best lemon blueberry sheet cake with lemon buttercream frosting. Both the cake and the homemade frosting are unbelievably good and it only takes less than an hour to make them both. Definitely a great recipe to have in your arsenal in case you need to make a cake on short notice! If you’re looking for a blueberry cake that’s just as easy, try this upside-down cake (or if you want to up the blueberry flavor, top it with this blueberry frosting instead of the lemon buttercream).
How to Make a Lemon Blueberry Sheet Cake
Follow these simple recipe instructions to make the lemon blueberry sheet cake:
- Preheat the oven. Preheat your oven to 350℉.
- Prepare the baking pan. Lightly grease a 9×13 inch baking pan.
- Prepare the blueberries. Add either fresh or frozen blueberries and 2 teaspoons of all-purpose flour to a bowl and toss to combine.
- Prepare the flour mixture. In a separate bowl, add the remaining flour, cornstarch, baking powder, baking soda and salt.
- Beat the eggs and sugar. Use the bowl of a stand mixer fitted with the paddle attachment to beat the eggs and granulated sugar.
- Finish off the wet mixture. Add the pure vanilla extract, lemon juice, lemon zest, buttermilk, melted butter and vegetable oil and beat until combined.
- Add the flour mixture. Add the flour mixture and beat until incorporated.
- Fold in the blueberries. Fold in the blueberries.
- Bake. Spread the batter into the prepared pan and bake in the preheated oven for 35 to 40 minutes (or until a toothpick inserted into the center of the cake comes out clean).
- Cool. Remove the cake from the oven and allow it to cool completely.
- Spread. Spread the homemade lemon buttercream frosting over the cooled cake (see below for details on how to make).
- Serve. Slice the cake and serve.
How to Make Lemon Buttercream Frosting
All that’s left to do now is prepare the yummy lemon buttercream frosting mixture to add to your lemon blueberry sheet cake:
- Beat the ingredients. Use the bowl of a stand mixer fitted with the paddle attachment to beat the softened butter, confectioners sugar and lemon juice, scraping the bowl occasionally, until the mixture is smooth and creamy (about 3 to 5 minutes).
- Spread. Spread the lemon buttercream frosting over the cooled cake.
P.S. If you need more ideas for treats, take a looks at our list of 48 Easy Blueberry Desserts
What is a Sheet Cake?
A sheet cake is simply a cake that is baked in a large rectangular pan; this is the main difference that sets them apart from regular cakes that use either 9×13 baking dishes or a couple of round pans for layered cakes. Sheet cake is usually made in a sheet pan or a jelly roll pan. They’re typically made in a variety of flavors and usually include a frosting spread.
2 Quick and Useful Tips When Applying Frosting
Here are a couple of quick tips to keep in mind when spreading your homemade lemon buttercream frosting over your lemon blueberry sheet cake:
- One direction only. Spread the frosting across the cake in an even layer going in one direction only.
- Keep at room temperature. You want your frosting to be at room temperature so that it’s easy to work with and spreads easily. Chilled frosting can be thicker and tougher to spread evenly.
Lemon Blueberry Sheet Cake with Lemon Buttercream Frosting
- Prep Time: 20 minutes
- Cook Time: 40 minutes
- Total Time: 1 hour
- Yield: 12 1x
For the cake:
- 3 cups plus 2 tsp all-purpose flour
- 1 tbsp cornstarch
- 2 tsp baking powder
- ½ tsp baking soda
- ½ tsp salt
- 4 large eggs
- 1 ½ cups granulated sugar
- ½ cup unsalted butter, melted
- ½ cup vegetable oil
- ¾ cup buttermilk
- 2 tbsp lemon zest
- ¼ cup lemon juice
- ½ tsp vanilla extract
- 2 ½ cups blueberries, fresh or frozen
For the frosting:
- ¾ cup unsalted butter, softened
- 3 cups confectioners sugar
- 3 tbsp lemon juice
- Preheat oven to 350ºF.
- Lightly grease a 9×13-inch baking pan.
- In a bowl add the blueberries and 2 teaspoons of flour and toss to combine.
- In another bowl combine the remaining flour, cornstarch, baking powder, baking soda and salt.
- In the bowl of a stand mixer fitted with the paddle attachment beat the eggs and sugar.
- Add the vanilla extract, lemon juice, lemon zest, buttermilk, melted butter and oil and beat until combined.
- Add the flour mixture and beat until incorporated.
- Fold in the blueberries.
- Spread the batter into the prepared pan.
- Bake in preheated oven at 350 ºF for 35-40 minutes or until a toothpick inserted in the center of a muffin comes out clean.
- Remove from the oven and allow to cool completely.
- To make the frosting, in the bowl of a stand mixer fitted with the paddle attachment beat the softened butter, confectioners sugar and lemon juice, scraping bowl occasionally, until smooth and creamy about 3-5 minutes.
- Spread the frosting over the cooled cake.