This basic galette recipe can be tailored to fit whatever fruit you have on hand. The key is to scale the amount of sugar and cornstarch. Generally speaking, tart stone fruits (apricots, peaches, nectarines, plums, sour cherries) need a greater amount of both sugar and cornstarch while figs, grapes, berries and Bing cherries tend to need less. If you’re unsure, add the sugar gradually, tasting as you go. Spreading a thin layer of jam over the rolled out dough before adding the filling bumps up the fruit flavor. You can match the jam flavors to your fruit or mix it up for a contrast. And if you don’t want to add lemon zest to the fruit, consider the seeds from a vanilla bean, ground spices, or some minced candied ginger instead. You can make the dough up to three days ahead, but this galette is at its best served the same day it was baked.
Add butter to flour mixture and pulse or use a pastry cutter or your fingers to break up the butter. If using a food processor, do not over-process; you need chickpea-size chunks of butter. Drizzle the egg mixture (up to 1/4 cup) over the dough and pulse or stir until it just starts to come together but is still mostly large crumbs. Mix in lemon juice and zest if using.
03Put dough on lightly floured counter and pat it together to make one uniform piece. Flatten into a disk, wrap in plastic and chill for 2 hours, or up to 3 days.
04Heat the oven to 400 degrees. Roll the dough out to a 12-inch round (it can be ragged). Transfer to a rimmed baking sheet lined with parchment paper and chill while preparing the filling.
05Make the filling:: Toss together fruit, all but a tablespoon of sugar, the salt, the lemon juice and zest, and the cornstarch. Use more cornstarch for juicy stone fruit and less for blueberries, raspberries and figs. Pile fruit on the dough circle, leaving a 1 1/2-inch border. Gently fold the pastry over the fruit, pleating to hold it in (sloppy is fine). Brush pastry generously with leftover egg and cream mixture. Sprinkle remaining sugar on the crust.
06Bake for 35 to 45 minutes, until the filling bubbles up vigorously and the crust is golden. Cool for at least 20 minutes on wire rack. Serve warm or at room temperature.