In a food processor, pulse together the flour, sugar, salt and cinnamon. Add in the vegan butter and pulse until it's the consistency of sand. Add in the ice water a little at a time until the dough forms a ball.
On a floured surface, work and shape the dough into a ball and then flatten into a disc. Wrap it in plastic and refrigerate for 1 hour.
Make the filling
While the dough is in the fridge, prepare the apples. Peel and thinly slice your apples and add them to a large bowl.
In the bowl with the apple slices, mix in the brown sugar, flour, lemon juice, vanilla extract, cinnamon, nutmeg and salt. Cover it tightly with plastic and let sit until the dough is ready. You can keep it at room temp or in the fridge.
Put galette together
Line a large baking sheet with parchment paper.
On a lightly floured surface, roll the dough into a circle about 12" wide. It doesn't have to be perfectly round. Carefully transfer the dough onto the prepared baking sheet.
Place the apple slices and any juice in the bowl into the center of the dough. You need to leave a 2-3" border of dough around them. You can either make a design (like in circles) with the apples or just spoon them in the center. Whichever way, try to keep them a bit flat - not a big mound in the center.
Next, fold the edges of the dough toward the center, one section at a time. The dough will overlap in places which is fine but try to press a little bit to seal the edges.
Place the unbaked galette in the fridge or freezer for 15-20 minutes while you're preheating the oven.
If you're using it, brush on some non-dairy milk onto the crust and sprinkle with the coarse sugar. This is optional.
Bake
Preheat the oven to 400℉. Place galette in the oven and bake for about 40 minutes. The crust should be golden brown.
Remove from the oven and let cool for about 10-15 minutes. Slice and serve! You can also top with some vegan vanilla ice cream or whipped cream.
Notes
Refrigerate any leftovers in the fridge for up to 4 days.
Use any kind of apples you like. You can also use 2 different varieties which I like to do.
Make sure your vegan butter is cold when making your crust. You can even put it in the freezer for about 10 minutes before using it.
If you don't have a food processor to help make the dough, you can use a pastry cutter or just 2 forks. Just mix the dry ingredients and then cut in the vegan butter. Add the ice water about 1 tablespoon at a time until it is the right consistency to form a ball of dough.
Refrigerating or freezing the unbaked galette before baking it helps it keep it's shape.
Be careful when you are moving it after it bakes so the crust doesn't break.