Jeanne Dwyer, mom of Team USA Olympic swimmer Conor Dwyer, shares a recipe for one of his favorite treats growing up.
Preheat the oven to 350 degrees F. Grease and flour a 9-inch square baking pan or line with parchment paper.
Whisk the flour, baking powder, baking soda, and salt together in a bowl. Set aside.
Cream the sugar and butter together with an electric mixer or stand mixer on medium speed. Reduce the speed to low and add the eggs, one at a time, then add the vanilla.
Add 1/3 of the flour mixture and stir on low speed until combined, then add half the sour cream, mixing until combined. Continue adding 1/3 more flour, the remaining sour cream, and then the rest of the flour.
Fold in the blueberries.
Pour the cake batter in to the prepared pan and spread the topping evenly over the batter.
Bake for about 1 hour until a knife or cake tester inserted into the center of the cake comes out clean.
Cool in the pan on a rack before slicing and serving.