In a food processor, combine the flour, ½ teaspoon of the salt and 1 tablespoon of the sugar. Pulse to combine. Scatter the cold butter cubes over top. Pulse until the mixture looks crumbly with pea-sized pieces of butter. Drizzle the apple cider vinegar over top. Turn the machine on and immediately start pouring ½ cup of the cold water through the feed tube. Stop once the dough starts to come together and looks shaggy—it should hold together when pinched (if needed, add another tablespoon of water).

Transfer the dough to a lightly floured surface and work it into a ball. Divide the ball in half and form two disks. Wrap the disks in plastic wrap. Refrigerate one disk for 30 minutes (or up to two days) and freeze the other disk for another galette or pie down the line!

Preheat the oven to 425 F.

In a bowl, toss the rhubarb with ⅓ cup of the sugar. Set aside while you make the almond filling, stirring occasionally.

In a clean food processor, combine the sliced almonds, the remaining ⅓ cup sugar, ¼ teaspoon of salt, 1 egg, vanilla extract, and almond extract. Process to a paste, stopping and scraping the sides occasionally, until the almonds are very finely chopped.

Transfer the chilled dough to a lightly floured piece of parchment paper. Roll the dough out into an ⅛-inch thick round (it should be about 11 inches in diameter). Brush off excess flour, then slide the parchment paper (with the dough) onto a baking sheet.

Spread the almond paste evenly over the dough, leaving a 2-inch border. Pile the rhubarb (and any sugar or juices from the bowl) over top, and arrange it in an even layer. Fold up the edges of the dough, pressing gently to seal. Refrigerate the galette for 5-10 minutes.

Beat the remaining egg with 1 teaspoon of water. Brush the edges of the galette with the egg wash (you won’t need it all). Sprinkle the edges with the turbinado sugar. Bake the galette until the crust is browned and the almond filling is golden in spots, about 30-35 minutes. Let the galette cool slightly before serving (it can be served warm or at room temperature).

Cut the galette into wedges and dollop with fresh whipped cream (recipe below), if you’d like!