4 from 9 votes

Buckwheat Apple Galette with Maple Walnut Frangipane {gluten-free, refined sugar-free}

The epitome of fall, toasty buckwheat flecks a flaky crust filled with maple walnut frangipane and a pretty mosaic of tart apple slices.
Prep: 30 minutes
Cook: 1 hour
Chilling time: 2 hours 50 minutes
Total: 1 hour 30 minutes
Servings: 9 -12 servings
Author: The Bojon Gourmet

Ingredients

Gluten-Free Buckwheat Crust:

  • 1/4 cup (60 ml) ice water
  • 1/4 cup (60 ml) cold buttermilk
  • 1/2 cup (80 g) sweet white rice flour (Mochiko)
  • 1/4 cup plus 2 tablespoons (40 g) GF oat flour, plus more for dusting
  • 1/4 cup (25 g) buckwheat flour
  • 1/4 cup (30 g) cornstarch
  • 2 tablespoons (13 g) tapioca flour
  • 2 1/2 tablespoons (15 g) finely ground chia seed
  • 1 tablespoon (10 g) Coombs Family Farms maple sugar
  • 1/2 teaspoon fine sea salt
  • 8 tablespoons (113 g) cold, unsalted butter (preferably European style), sliced 1/4-inch thick

Maple Walnut Frangipane:

  • 1 cup (90 grams) raw walnut halves
  • 6 tablespoons (60 grams) Coombs Family Farms maple sugar
  • 1/4 cup (40 grams) sweet rice flour
  • 1/4 teaspoon fine sea salt
  • 4 tablespoons (56 grams) unsalted butter, softened
  • 2 large eggs

To Finish:

  • 5 medium granny smith or other tart baking apples (about 1 ¾ pounds / 800 g)
  • juice from ½ a lemon
  • 2 tablespoons unsalted butter, cut into tiny cubes
  • 2 tablespoons Coombs Family Farm maple syrup (either amber or dark), plus more for drizzling
  • 1 egg, beaten well
  • crème fraiche, whipped cream, or vanilla ice cream, for serving
  • flaky salt, for serving

Instructions

Make the crust:

  • Combine the ice water and buttermilk in a small pitcher and chill until needed. In the bowl of a food processor, combine the sweet rice, oat, and buckwheat flours with the cornstarch, tapioca flour, ground chia seed, sugar, and salt. Scatter the butter pieces over the top and place the lid on the food processor, but don’t process yet! Simultaneously pour the cold buttermilk mixture through the feed tube in a slow and steady stream while pulsing the food processor all the while until all the liquid is added and the butter is broken down into chunks of varying sizes from tiny peas to lima beans. The dough should hold together when squeezed; if it needs more liquid to come together, gently pulse in a tablespoon or two more ice water.
  • Press the dough into a ball, flatten into a disc in a large piece of plastic wrap or beeswax wrap, wrap tightly, and chill until firm, at least 1 hour and up to 3 days.
  • Let the dough soften at room temperature for 10 – 20 minutes to make it easier to roll. On a surface dusted lightly with oat flour, roll the chilled dough out into a rough square that is about ¼-inch thick. As you work, dust the top of the dough with oat flour, using a dry pastry brush to sweep away the excess. When the dough begins to stick to the work surface, use a bench scraper to move it to one side, dust the surface with more flour, and return the dough to the surface to continue rolling. Don’t worry if the dough crumbles and wants to fall apart, just press it back together. Once the dough is rolled out, fold it in thirds like folding a letter, then roll it up from a skinny end into a loose spiral. Gently press to flatten it slightly, and chill for 30 minutes. Optionally (preferably), repeat this step once more. The dough will get smoother and easier to work with as you make these turns.

Make the frangipane:

  • In the bowl of a food processor, combine the walnuts, maple sugar, sweet rice flour, and salt. Process to a fine powder. Add the butter and eggs and process until silky smooth. Chill until needed.

Assemble the tart:

  • Position a rack in the upper third of the oven and preheat to 400ºF.
  • Let the dough stand at room temperature until slightly softened, 5 minutes in a warm kitchen or 15 minutes in a cool kitchen. Sandwich the dough between 2 large pieces of parchment paper dusted lightly with oat flour, and gently begin pressing it flat, then roll it into a 12 by 16-inch (30 by 40-cm) rectangle. As you work, periodically peel back the top piece of parchment, dust the dough lightly with oat flour, replace the parchment, grasp the dough sandwich with both hands and flip the whole thing over. Peel off the new top piece of parchment, dust with flour and continue to roll. If the dough is uneven, cut off the long bits and press them onto the short bits, rolling to adhere. When your rectangle measures 12 by 16 inches (30 by 40 cm), trim the sides so that they’re even and straight. If your dough becomes soft or sticky at any point, slip it onto a baking sheet, parchment and all, and chill it for 10–20 minutes to firm the butter. When the crust is rolled out, spread the frangipane over it in an even layer leaving a 1-inch border on each side. Slide the crust onto a baking sheet (unrimmed if you’ve got one), still on the parchment, and chill until firm, 20 minutes.
  • While the crust chills, use a T-shaped vegetable peeler to peel the apples. Holding each apple upright, cut the flesh away from the core in 4 or 5 large pieces. With a cut-side down, cut each apple piece lengthwise into 1/8-inch thick slices, keeping the pieces together and discarding (or noshing on) the rounded end pieces. Drizzle the apples with the lemon juice to prevent them from oxidizing and to up the acidity.
  • When the crust has chilled, place slices from about one-quarter of an apple (roughly 5 slices) over the top corner of the frangipane lengthwise, fanning and flattening them them out slightly. Place another quarter of an apple next to the first quarter crosswise snuggling them as close to the first apples as you can (they will shrink a bit in the oven). Repeat with the remaining apples, making a crosshatch pattern and placing the apples close together. Use the parchment to help fold the dough edges over the apples to make a crust, pressing the corners to adhere. Dot the apples all over with the butter and drizzle with the 2 tablespoons maple syrup. Brush the edges of the dough with the beaten egg. If the dough has become soft to the touch, chill until firm, 15-30 minutes.
  • Bake the tart until the apples have begun to caramelize around the edges and the bottom of the crust is crisp, 40-50 minutes, rotating after 30 minutes for even baking. Let cool to warm or room temperature. Drizzle all over with maple syrup, dust with pinches of flaky salt, cut into squares, and serve with crème fraiche. The tart is best the day of baking when the crust is crisp, but extra tart keeps well, refrigerated airtight, for up to 3 days. For best reheating results, place a slice in a skillet set over low heat until the crust is crisp and the topping is warm, about 5 minutes.

Notes

This galette is best the day of baking when the crust is crisp, but the buckwheat pie dough and maple walnut frangipane can both be made up to 3 days in advance and refrigerated airtight until you’re ready to bake.
If making my GF pie dough for the first time, I recommend having a quick read-through of my process and base recipe here, complete with step-by-step photos. I prefer to make the dough in a food processor, which helps make the dough extra supple to work with, but you can also use a pastry blender to cut the butter into large pea-sized pieces, tossing in the cold liquid with a flexible spatula, if you prefer.
Nutritional values are based on one of nine servings.

Nutrition

Calories: 481kcal | Carbohydrates: 51g | Protein: 7g | Fat: 30g | Saturated Fat: 13g | Cholesterol: 102mg | Sodium: 229mg | Potassium: 288mg | Fiber: 5g | Sugar: 24g | Vitamin A: 690IU | Vitamin C: 6.1mg | Calcium: 79mg | Iron: 1.5mg
Making this? I'd love to see!Tag your snaps @The_Bojon_Gourmet and #bojongourmet!