Georgia Peaches-and-cream Cake

CRUMB TOPPING
1/2 c Unbleached all-purpose flour 4 tb Unsalted butter; chilled
6 tb Light brown sugar 1/4 ts Cinnamon

CAKE
6 tb Sour cream 1 1/2 ts Pure vanilla extract
1/4 ts Baking soda 3/4 c Unbleached all-purpose flour
1 lg Egg 1/2 ts Baking powder
1/3 c Sugar 1/4 ts Salt
4 tb Unsalted butter; softened

PREHEAT OVEN TO 375F 15 minutes before baking, with the rack in the
center of the oven. Butter an 8-inch square baking pan, preferably
glass. Cut the peaches into 1/2-inch slices. Put in a pan with sugar,
lemon juice, tapioca and nutmeg and toss gently. Cook over high heat
until syrup begins to bubble, about 4 minutes. Set aside.

FOR THE TOPPING: Work the flour into the sugar, butter and cinnamon
until the butter is the size of small peas. This can be done with a
food processor or pastry blender. Set aside.

FOR THE CAKE: Stir the sour cream and baking soda together and let
stand while you begin the cake. Cream the egg, sugar and butter in
the processor or with a mixer until it is light and fluffy. Add the
vanilla and sour cream and mix well. Gently fold in the flour, baking
powder and salt. In the processor, do this by pulsing the machine on
and off several times. Spread the warm peaches and their juice in the
bottom of the baking pan. Spoon the batter over the peaches and
spread in a thin, even layer with a rubber spatula. It’s OK if the
peaches are not completely covered. Sprinkle the topping over the
batter. Bake until a toothpick inserted into the center of the
cake–not the fruit–comes out clean, 25-to-28 minutes.