01 - Preheat oven to 350°F. Grease and line two 8-inch round cake pans with parchment paper.
02 - In a medium bowl, whisk together flour, baking powder, and salt until well blended.
03 - In a large bowl, beat butter and sugar together on medium-high speed until light and fluffy, about 3–4 minutes.
04 - Add eggs one at a time, mixing well after each addition. Stir in vanilla extract until incorporated.
05 - With mixer on low, add flour mixture in three additions, alternating with the milk, beginning and ending with flour. Mix until just combined.
06 - Gently fold in the chopped strawberries, then the sprinkles, being careful not to over-mix to prevent colors from bleeding.
07 - Divide batter evenly between the prepared pans. Smooth the tops. Bake for 28–32 minutes, or until a toothpick inserted in the center comes out clean.
08 - Let cakes cool in pans for 10 minutes, then turn out onto wire racks and cool completely before frosting.
09 - Beat butter on medium speed until creamy, about 2 minutes. Gradually add the powdered sugar, mixing on low speed.
10 - Add the strawberry puree, vanilla, and salt. Beat until smooth and fluffy. Add milk a tablespoon at a time if frosting is too thick.
11 - Place one cake layer on a serving plate. Spread with a layer of strawberry buttercream. Top with second cake layer and frost the top and sides with remaining buttercream.
12 - Decorate with extra sprinkles if desired. Slice and serve immediately or store as directed.