Preheat oven to 350°F (175°C). Line an 8x8-inch pan with parchment.
Mix flour, sugars, and salt for the crumb topping; add melted butter and form large crumbs. Set aside.
Whisk melted butter, sugar, vanilla; add eggs one at a time, then sour cream. Sift dry ingredients and fold into wet mixture. Add milk and combine. Spread batter in pan.
Mix strawberries with flour and sugar, then layer over batter. Scatter crumb topping on top.
Bake for 40-50 minutes until golden and firm. Cool for 30 minutes before serving.
Notes
Use fresh strawberries for best flavor and texture.