1. Preheat the oven to 400°F (200°C). To make the dough, stir the flour and sugar together in a bowl. Add the butter and rub it with your fingertips until the mixture resembles coarse bread crumbs. Mix the egg yolk with 3 tbsp cold water, add the flour mixture, and stir.

2. On a lightly floured surface, roll the dough into a 1/8 in (3mm) round circle and use to line a 9in (23cm) tart pan with a removable bottom. Prick it lightly all over with a fork. Chill for 30 minutes. Line the dough with wax paper and fill with baking beans. Bake for 10 minutes. Remove the paper and baking beans and bake for 10 minutes more, until the crust is golden and crisp. Remove from the oven. Reduce the oven temperature to 350°F (180°C).

3. Beat the cream cheese, sugar, sour cream, eggs, lemon zest, and nutmeg with an electric mixer until well combined. Spread in the tart shell and top with the blueberries. Bake for 25–30 minutes, or until the filling is just set. Transfer to a wire rack and let cool. Remove the sides of the pan. Sift confectioner's sugar over the top, slice, and serve.

Variation:

Raspberry Cream Cheese Tart: Use the same quantity of fresh raspberries in place of the blueberries.