Preheat oven to 350°F (175°C). Grease and flour two 9-inch round pans; line bottoms with parchment paper.
Sift flour, sugar, baking powder, and salt into a bowl. Whisk to remove clumps.
Cream softened butter and sugar until light and fluffy. Add eggs one at a time, beating well after each.
Alternate adding dry ingredients and buttermilk to the egg mixture, beginning and ending with dry. Fold in vanilla and 1 cup strawberries.
Divide batter between pans. Bake 28-32 minutes until golden and a toothpick comes out clean. Cool completely in pans on wire racks.
Whisk ½ cup flour, ¾ cup sugar, crushed butter, and vanilla until crumbly. Spread over one cooled layer.
Stack layers, then cover with remaining topping and sliced strawberries. Refrigerate 1 hour before serving.