Rhubarb Frangipane Galette With Spelt Crust

Directions

1. In a large bowl, combine the spelt flour, sugar, and salt. Add the chilled butter cubes and use your hands or a pastry cutter to press the flour into the butter until the butter is the size of small peas and the dough resembles coarse sand. Slowly pour in half of the cold water and mix with a fork. Add the remaining water where the dry spots are. Shape the dough into a ball and flatten it out slightly. Wrap the dough in plastic wrap and refrigerate until firm, about 30-40 minutes.
2. In the meantime, make the frangipane. In a food processor, combine the almonds, ¼ cup of the sugar, flour, and salt and blend until the almonds are finely ground (see Tips & Tricks). Add 3 tablespoons of the butter (save the rest for assembling), egg white, vanilla and almond extract, 1 tablespoon of the orange zest, and 1 teaspoon of the orange juice. Pulse into a smooth paste.
3. Preheat the oven to 400ºF/204ºC. Unwrap the chilled pie dough and place it on a piece of parchment paper. Sprinkle flour on both sides, then use a rolling pin to roll the dough into a 12-inch wide circle. Prick holes all over with a fork.
4. Before cutting the rhubarb, place the stalks on top of the dough to see where to trim the fruit to fit, while also leaving a 2-inch border around the edges to fold over the rhubarb. The center pieces will be longer than the edge pieces, similar to making strips of dough for a lattice crust. Once you’ve measured and cut the rhubarb pieces into the right lengths, slice each piece lengthwise into three pieces. Place the crust back in the fridge and chill for another 10 minutes.
5. While the crust chills for the second time, prepare the egg wash and the orange sugar. In a small bowl, mix the egg yolk and 1 tablespoon of water. In a second small bowl, combine the remaining 1 tablespoon orange zest and 1 tablespoon sugar; press and rub it between your fingers so that the orange infuses into the sugar. Set both aside.
6. Remove the crust from the fridge. Spread the frangipane into an even layer across the crust, leaving a 2-inch border all around. Arrange the sliced rhubarb stalks on top of the frangipane, with the longest pieces in the middle to make it look circular. Fold the edges up over the sides of the rhubarb, pressing on them gently to adhere.
7. Sprinkle the rhubarb with the orange sugar and dollop evenly with the remaining 1 tablespoon of butter. Drizzle the remaining 2 teaspoons orange juice over top. Brush the edges with the egg wash and sprinkle all over with demerara sugar.
8. Bake the galette until the rhubarb is tender, the frangipane is slightly puffed, and the crust is a deep golden brown, 35 to 40 minutes.
9. While the galette is baking, whip the heavy cream and mascarpone until soft peaks form. Serve the warm galette dolloped with mascarpone whipped cream.