15ouncesfresh blueberries(frozen may be substituted; don't defrost)
Prepare the Topping
Combine the sugar, flour and nutmeg in a small bowl. Add butter, then use a pastry blender, fork or clean fingers to combine the ingredients until they have a crumb-like texture (a few larger pieces of butter here and there are fine).
Prepare the Cake
Place an oven rack on the center shelf, then preheat the oven to 375 degrees F. Spray a 9-inch square glass baking dish with nonstick cooking spray and set aside.
Whisk the flour, baking powder, salt and ginger together in a medium-sized bowl.
In a stand mixer fitted with the paddle attachment, cream the butter and sugar together on medium speed until light and fluffy, approximately 1-2 minutes (longer if your butter isn’t fully at room temperature). Reduce the speed to low and thoroughly incorporate the egg. Add one-third of the flour mixture. Once incorporated, add one-third of the milk, then repeat alternating the wet and dry ingredients until everything is combined.
Stir in the blueberries, then pour the mixture into the prepared baking dish and sprinkle the topping on evenly.
Bake for 40-45 minutes, or until golden brown on top. Cool for 30 minutes before serving.
Leftovers will keep in an airtight container in the refrigerator for up to one week.
You can make homemade cake flour using all-purpose flour. Simply measure out the all-purpose flour, then remove 2 tablespoons. Add 2 tablespoons of cornstarch and whisk together until evenly combined. If you don’t have cake flour OR cornstarch, this recipe will still work with all-purpose flour; it just won’t have as soft of a texture.Adapted from Alton Brown