| 1 | Preheat oven to 350°F. |
| 2 | Pastry: place flour, sugar and salt in a medium size mixing bowl. |
| 3 | Cut in the chilled butter, then rub mixture with your finger tips until it resembles coarse crumbs. |
| 4 | Sprinkle with the vinegar and shape gently into dough. |
| 5 | Press dough into an ungreased 9-inch round cake pan to a thickness of about ?inch. |
| 6 | The crust should be worked to 1 inch up the sides of the pan. |
| 7 | Filling: place the 3 cups of blueberries on the crust. |
| 8 | Mix the sugar and cinnamon into the flour and sprinkle evenly over the berries. |
| 9 | Place in the oven on the lowest rack and bake for 50 minutes or until the crust is golden and the filling bubbles. |
| 10 | Remove from the oven and immediately sprinkle with the remaining 2 cups of blueberries. |
| 11 | Let the kuchen rest at room temperature for about an hour. |
| 12 | Then sprinkle with the powdered sugar and serve |
