Preheat & Prep: Preheat oven to 350°F (175°C). Grease and line a 9-inch springform pan with parchment paper.
Mix Dry Ingredients: In a medium bowl, whisk together flour, baking powder, cinnamon, and salt.
Cream Butter & Sugar: In a large bowl, beat softened butter with sugar until light and fluffy. Add eggs one at a time, then stir in vanilla.
Add Ricotta: Fold in ricotta until well combined.
Combine Wet & Dry: Add the dry ingredients to the wet mixture, folding gently until just combined.
Add Peaches: Fold in chopped peaches, reserving a few slices for topping. Spread the batter evenly in the prepared pan.
Make Streusel: Brown the butter in a saucepan until golden and nutty. In a separate bowl, mix flour, brown sugar, and salt. Stir in the browned butter with a fork until crumbly.
Top & Bake: Sprinkle streusel evenly over the batter. Bake for 45–55 minutes, or until a toothpick inserted in the center comes out clean.
Cool & Serve: Cool in the pan for 10 minutes, then release the springform and let the cake cool fully on a rack. Slice and serve.