Roll the chilled pastry on a lightly floured surface into a very thin, roughly shaped circle, 14 inches in diameter. If the dough is very firm, let it sit at room temperature about 10 minutes or tap the pastry gently all over with the rolling pin to flatten it a bit, then roll it out. Use even strokes, working from the center of the dough out towards the edges.
You may not think the dough will be able to become 14 inches in diameter, but it will. (If the dough feels too soft, fold it in half, transfer it to the pizza pan or rimmed baking sheet, unfold it, and refrigerate a few minutes.)
Do not be concerned about rough edges of dough or if your circle is not perfect. This is rustic. What’s important is that the dough is thin, thin, thin. The butter flakes melt during baking and the pockets of air that are formed make the pastry flaky.
Transfer the dough to the pizza pan or rimmed baking sheet. Sprinkle the ground almonds and flour onto the center of the dough and distribute with your fingers into a thin powdery circle about 11-inches in diameter.
Begin arranging the apricots on the ground almonds and flour.
Arrange the apricot halves in concentric circles on the nut layer. I make three or four circles, beginning with the outermost. If you have smaller fruit, arrange them in one or two more circles than suggested.
Scatter the cold butter bits over the fruit, and sprinkle evenly with 6 tablespoons of the sugar.
Bring up edges of the pastry to cover the outer edge of apricots and press gently to adhere. Brush the pastry edge with water and sprinkle with the remaining 1 tablespoon sugar.
Put the galette into the oven and bake for 45 to 50 minutes, or maybe even longer, until the apricot juices bubble thickly, like a syrup, and the fruit and pastry are well-browned with random darker spots. The sugar must be well caramelized.
Cool the galette on its pan for 10 to 15 minutes, then transfer with a wide metal spatula to a wire cooling rack. Sometimes juices leak onto the pan during baking causing the galette to stick, so loosen the galette carefully to avoid tearing the pastry.
Apricot galette is best when very fresh. Serve it plain. It needs nothing extra.
Note: I’ve successfully reheated leftover galette the next morning in a preheated 400 degree oven for 5 minutes.