Preheat your oven to 350°F (175°C). Grease a 9-inch springform pan and line the bottom with parchment paper to prevent sticking. Set the pan aside until ready to use.

In a bowl, mix together the softened cream cheese and 1/4 cup sugar on medium-low speed until smooth and creamy. Add the egg white and mix on low speed just until combined. Set this filling aside.

In a small bowl, stir together 1 1/2 cups flour, 1/2 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/4 teaspoon salt. In a separate large bowl, cream 5.5 tablespoons softened unsalted butter and 1/2 cup sugar with an electric mixer on medium-low speed until fluffy. Add the egg, extra egg yolk, and vanilla extract, mixing until incorporated. Slowly add the flour mixture to the wet ingredients, alternating with the sour cream, mixing just until combined. Transfer the batter to the prepared pan and smooth the top with a spatula.

Spread the prepared cream cheese filling (from Step 2) evenly over the cake batter in the pan. Gently place the raspberries on top of the cream cheese layer, distributing them evenly.

In a bowl, combine 1/2 cup flour, 1/3 cup sugar, and 3 tablespoons chilled, cubed butter. Use a fork or pastry blender to mix until the mixture is crumbly and the pieces resemble pea-sized crumbs. I find using very cold butter helps give the streusel the perfect texture.

Sprinkle the streusel topping (from Step 5) evenly over the raspberries. Transfer the pan to the oven and bake at 350°F (175°C) for 40–45 minutes, or until a cake tester inserted into the center comes out clean. Let the cake cool on a rack before carefully running a thin knife around the edge and releasing the springform ring. I like to let the cake cool completely for the cleanest slices.