Step 1

Stir together the flour, cornmeal, baking powder, baking soda, and salt in a medium bowl. Set aside.

Step 2

Preheat the oven to 350°. Butter a 9-inch deep dish pie plate, and set it aside. Beat 1/2 cup butter and brown sugar until fluffy, about 3 minutes. Add the egg and vanilla, and beat until just combined. Add half of the flour mixture, the buttermilk, then the remaining flour, beating until combined after each addition.

Step 3

Spoon the batter into the prepared pie plate; spread in an even layer using the back of a spoon or a spatula. Scatter the berries evenly over the top of the batter; do not press them down. Sprinkle the berries and batter with 2 tablespoons turbinado sugar, if using.

Step 4

Bake until the top is golden brown and a wooden pick inserted into the cake (not a strawberry!) comes out clean, 40 to 45 minutes. Let cool before dusting with powdered sugar and serving with more sliced strawberries, if you like.