Blueberry Cornmeal Cake

1 cup plus 2 tablespoons self-rising flour
3/4 cup fine cornmeal
1/8 teaspoon salt
3/4 cup softened unsalted butter
2/3 cup plus 3 tablespoons granulated sugar
1 large egg
2 cups blueberries, lightly rinsed and dried
1 tablespoon confectioners' sugar, for dusting

Let the cake sit 1 to 2 hours on a wire rack before unmolding and slicing, so it holds together well. Preheat the oven to 375 degrees Sift the flour, cornmeal and salt together in a medium-sized bowl; set aside. Beat the butter and 2/3 cup of granulated sugar with an electric mixer at medium speed. Add the egg and beat well. Add the flour mixture at low speed and mix until just blended. Press three-fourths of the dough evenly over the bottom of an 8 1/2-inch springform pan and about 1 inch up the side 5. Toss the blueberries in a bowl with 3 tablespoons of granulated sugar and pour them over the dough in the pan. Top the blueberries with the remaining dough, pinching it off in small amounts and arranging it evenly over the surface. Bake the cake in the center of the oven until nicely browned, 40 to 50 minutes, covering the top with aluminum foil if it browns too quickly. Cool in the pan on a rack for 1 to 2 hours before slicing. Just before serving, dust with confectioners' sugar and remove sides of pan. Serves 8.