For the crumb topping:
For the cake:
Preheat the oven to 350˚ F. Lightly grease and flour and 10-inch springform pan. To make the crumb topping, combine the flour, granulated sugar and lemon zest in a small bowl and whisk to blend. Add the melted butter and stir with a fork until the mixture is crumbly. Set aside.
To make the cake, combine the flour, sugar, baking powder, baking soda and salt in a large bowl. In another bowl, whisk together the eggs, sour cream and vanilla until well blended. Make a well in the center of the flour mixture and add the liquid ingredients. Fold together gently until evenly mixed and no streaks remain, being careful not to over mix. Spread the batter into the prepared pan in an even layer. Dot the top of the batter with the raspberries. Sprinkle the crumb topping evenly over the berries.
Bake until the topping is golden brown and a toothpick inserted into the center of the cake comes out clean, 38-42 minutes. Transfer the pan to a wire rack and let cool for 20 minutes. Remove the sides of the springform pan. Serve warm or at room temperature, cut into wedges.