Step 1

Position the rack in the middle of the oven. Preheat oven to 350F. Coat the insides of 3-6 inch cake pans with non-stick cooking spray, line bottoms with parchment paper rounds, then spray parchment.

Step 2

Whisk together sifted flour, baking powder and salt in a medium size bowl to combine. Set aside. In a blender, combine milk, egg whites and spinach, blend until well combined and smooth. Set aside.

Step 3

Beat butter until creamy, about 2 minutes, with an electric mixer on medium-high speed. Add sugar gradually and beat until very light and fluffy, about 3 minutes, scraping down the bowl once or twice. Beat in the vanilla.

Step 4

Add flour mixture in three additions, alternately with the milk-spinach mixture, while beating on low speed. Begin and end with flour, and beat briefly until smooth. Divide the batter evenly between the 3 cake pans and smooth the tops with a spatula.

Step 5

Bake for 40-45 minutes, or until a toothpick inserted into layers shows a few moist crumbs when removed. The layers will be a light golden brown around the edges and top and will have come away from the sides of the pans.

Step 6

Cool the pans on a wire rack for 8-10 minutes. Unmold, peel off the parchment, and place the layers directly on the racks to cool completely.

Step 7

Spinach Buttercream Frosting

Step 8

In a blender combine milk and spinach. Blend until well combined.

Step 9

In a large bowl, with an electric mixer or a stand- mixer on medium-high, beat butter until creamy, about 2 minutes. Add one cup of sugar gradually, beating until light and fluffy about 3 minutes, scraping down the bowl once or twice. Add remaining sugar, milk-spinach mixture, vanilla and beat on high until silky smooth.

Step 10

Cut off the very top of the cake to make all three layers even.

Step 11

Place on 6 inch cake on a platter and spread 1/3 cup of the frosting. Top with another 6 inch cake and spread 1/3 cup frosting. Top with remaining 6 inch cake and use remaining frosting to cover the cake.

Step 12

Note: The Spinach Smash Cake can sit at room temperature for 24 hours, refrigerate for 3 days or cakes can be individually wrapped and frozen up to 3 months.