Preheat oven to 350°F (175°C)
Grease and line two 8-inch cake pans
Mix flour, baking powder, and salt in a bowl
Cream butter and sugar until light and fluffy
Beat in eggs one at a time
Add vanilla extract
Add strawberry puree or mashed strawberries
Add dry ingredients alternately with milk
Mix until just combined
Divide batter evenly between pans
Bake for 25 to 30 minutes
Cool in pans for 10 minutes
Remove cakes and cool completely
Beat butter, powdered sugar, strawberry puree, and vanilla for frosting
Place one cake layer on a plate
Spread frosting on top
Add second cake layer
Frost top and sides
Garnish with sliced strawberries if desired