- 2 1/2 cups cake flour (see note below)
- 1 1/2 tsp baking powder
- 1/2 tsp baking soda
- 1/2 tsp salt
- 10 Tbsp unsalted butter, at room temperature
- 1 1/2 cups sugar
- 2 Tbsp citrus zest
- 2 tsp vanilla extract
- 2 large eggs, at room temperature
- 1 cup low-fat buttermilk, at room temperature
- 1/4 cup plain fat-free Greek yogurt, at room temperature
- 2 Tbsp citrus juice
- 1/2 cup unsalted butter, at room temperature
- 2 oz full fat cream cheese, cool room temperature
- 1/4 tsp salt
- 1 Tbsp citrus zest
- 1 tsp vanilla extract
- 3 cups powdered sugar
- 1/2 Tbsp citrus juice
- Preheat oven to 350°F and spray a 13 x 9-inch baking pan with nonstick spray. Whisk together cake flour, baking powder, baking soda, and salt in a medium bowl.
- Combine sugar and citrus zest in a food processor and pulse for 1 minute. Beat butter and citrus-sugar in a large mixer bowl at medium speed until light and fluffy; beat vanilla. Add eggs one at a time and beat until combined. Combine buttermilk, Greek yogurt and citrus juice in a small bowl. Reduce speed to low and add flour mixture in 3 additions, alternating with buttermilk mixture (begin and end with flour mixture).
- Spoon batter into prepared baking pan and smooth with an offset spatula. Tap pan sharply to reduce air bubbles. Bake for 24 to 26 minutes, until the top and edges are golden and a toothpick inserted in the center comes out clean or with a few crumbs attached. Cool cake completely in pan on a wire rack.
- For the frosting, beat butter, cream cheese, and salt in a large mixer bowl on medium speed until smooth. Beat in citrus zest and vanilla. Mix in powdered sugar on low speed 1 cup at a time until fully incorporated. Add citrus juice and mix in on low speed until smooth.
- Dollop frosting over cooled cake and swirl with an offset spatula. Top with sprinkles, then chill cake for 20 minutes in the refrigerator before slicing and serving.
To make your own cake flour: place 2 tablespoons cornstarch in an empty 1-cup measure, then top up with flour. Sift the mixture several times to evenly distribute the cornstarch.
Keywords: Citrus, Vanilla, Sheet Cake, Cake