| 1 | Preheat oven to 375°F, 15 minutes before baking, with the rack in the center of the oven. |
| 2 | Butter an 8" square baking pan, preferably glass. |
| 3 | Cut the peaches into ? slices. |
| 4 | Put in a pan with sugar, lemon juice, tapioca and nutmeg and toss gently. |
| 5 | Cook over high heat until syrup begins to bubble, about 4 minutes. |
| 6 | Set aside. |
| 7 | For the topping: work the flour into the sugar, butter and cinnamon until the butter is the size of small peas. |
| 8 | This can be done with a food processor or pastry blender. |
| 9 | Set aside. |
| 10 | For the cake: stir the sour cream and baking soda together and let stand while you begin the cake. |
| 11 | Cream the egg, sugar and butter in the processor or with a mixer until it is light and fluffy. |
| 12 | Add the vanilla and sour cream and mix well. |
| 13 | Gently fold in the flour, baking powder and salt. |
| 14 | In the processor, do this by pulsing the machine on and off several times. |
| 15 | Spread the warm peaches and their juice in the bottom of the baking pan. |
| 16 | Spoon the batter over the peaches and spread in a thin, even layer with a rubber spatula. |
| 17 | It"s ok if the peaches are not completely covered. |
| 18 | Sprinkle the topping over the batter. |
| 19 | Bake until a toothpick inserted into the center of the cake, not the fruit, comes out clean, 25-28 minutes. |
