Add dry ingredients (almond flour, arrowroot, salt) to a food processor and pulse to combine. Add the cold butter, honey, ice cold water, and egg (less 2 teaspoons reserved for egg wash). Pulse until a dough forms. Small chunks of butter remaining are perfectly fine!

Alternatively you can combine ingredients in a bowl and use a pastry cutter or knife to mix in the butter.

Let chill in fridge for 30 minutes.

Preheat the oven to 375ºF.

Meanwhile, slice the apples as thinly to do this. I recommend cutting them in half, then quarters, then carefully removing the core. Place two quarters close together with the flat side down and slice as thinly as you can - about 1/16th - ⅛th inch thick. Unevenness is perfectly okay here!

Place sliced apples in a large bowl and combine with cinnamon, maple syrup, lemon juice, and vanilla extract. Stir gently to coat each slice.

You can skip lemon juice if preferred - it's a great balance and helps to soften the apples, but if you don't have any - leave it out!

Place parchment paper on flat surface. Roll the dough into a circle until about ¼th inch thick. It should make a 10-12 inch circle/oval. Transfer parchment paper to a sheet pan / baking sheet.

Layer the apple slices across the dough in straight lines or in concentric spiraling formation (see images above). I rotated red and green slices for the photos here (which took about 7 minutes), but that is not necessary. If any liquid remains in the bowl, I recommend drizzling this over the apples.

When ready to 'close' the galette, lift the parchment paper to fold the dough over the vegetables (see images above). Continue around the circle to gently fold the dough over the outer 1-2 inches of the vegetables, forming pleats. If anything tears or if apples poke through, just press the dough back together. You can also pull extra dough from the center to patch things up. Remember: galettes are meant to be rustic!

Use a pastry brush for the egg wash, (which means you brush the remaining whisked egg over the top of the pastry dough). Without a pastry brush, you may be able to use a spoon or your fingers. Sprinkle 1-2 teaspoons of chunky sugar like turbinado over the outer top crust for a fun and classic texture.

Bake the galette on 375ºF for 30-35 minutes or until top is golden brown and bottom is cooked through and not soggy.

Let cool for a few minutes before slicing, then cut into about 6 pieces.

Top with fresh ice cream or whipped cream and serve warm!