Preheat oven to 350℉. Line a 9” cake pan with parchment paper and lightly coat with nonstick spray. Whisk flour, sugar, baking powder, and salt in a large bowl.
Whisk eggs, ricotta, and vanilla in a medium bowl until smooth; fold into dry ingredients just until blended. Then fold in butter, followed by 6 oz. raspberries. Some will streak on you, this is fine. Scrape batter into prepared pan and scatter about 3 oz. raspberries over top. Don’t be too exacting with this step, you just want somewhat evenly spaced raspberries all over your cake.
Bake cake until golden brown and a tester inserted into the center comes out clean, 50–60 minutes. When you are testing your cake, you must, must, must dip the tester into a spot right next to the raspberries. Those parts of the cake bake more slowly than the rest, so it’s not enough to just get a clean tester in the middle of the raspberries. The cake is not done until it comes out clean after poking right by the raspberries.
Let cool at least 20 minutes before unmolding.