Preheat oven to 350°F and prepare baking pan.
Slice peaches and set aside.
Beat butter and sugar until fluffy.
Mix eggs and vanilla into creamed mixture.
Combine dry ingredients separately.
Alternate adding milk and dry mix to the batter.
Spread batter into the baking pan.
Lay peach slices evenly on top.
Lightly press peaches into batter.
Mix topping ingredients with pastry cutter.
Add crumb topping over peaches.
Bake 45–50 minutes until golden and set.
Let rest 15–30 minutes before serving.