Preheat oven to 375.
Grease an 8-inch cake pan or springform pan with baking spray. Line a baking sheet with foil and set the springform pan on the baking sheet.
Arrange the sliced peaches on the bottom of the cake pan.
In a small mixing bowl, combine lemon juice and corn starch; mix until thoroughly combined.
Drizzle lemon mixture over peaches.
Sprinkle brown sugar over peaches; set aside.
In a small mixing bowl, whisk together flour, baking powder, and baking soda; set aside.
In your mixer's bowl, cream together butter and sugar until smooth, light and fluffy.
Add egg and continue to beat until completely combined.
Mix in zest and vanilla.
Set mixer on "low" and add flour mixture in batches, alternating with ricotta, and beginning and ending with flour.
Continue to beat until well combined.
Pour batter over peaches.
Using an offset spatula, gently spread the batter evenly and smooth it out.
Bake for 30 to 35 minutes, or until a toothpick inserted in the center of the cake comes out clean.
Let completely cool.
Remove cake by covering up the pan tightly with a serving dish and invert so that the side with peaches is up.
Drizzle with blueberry-preserves juice.
Cut and serve.