Add in your lemon juice, brown sugar, spices, salt, and vanilla extract. Stir to combine well and set aside.

Begin working on the galette dough. Add the flour, sugar, and salt together into a food processor and pulse 1 - 2 times to combine.

Add the butter and pulse about 4 - 6 times, or until the mixture looks like large crumbs.

Drizzle in one tablespoon of ice water and pulse 1 - 2 times. Check the dough by pressing it in your hands. If it sticks together, it is ready. If it does not stick together, repeat the process with another tablespoon of ice water. Continue going until the mixture will stick together when pressed together.

Place the dough onto a sheet of plastic wrap and form into a disc. Chill for about 30 minutes.

Use a rolling pin to roll out the dough into a 12 - inch circle on a lightly floured surface. Transfer the dough onto a baking sheet lined with parchment paper.

Place the baking sheet with the galette in the freezer and preheat the oven to 375F.

Remove the baking sheet and make your egg wash. Brush over the folded over galette dough and then sprinkle with sugar.

Bake for about 45 - 50 minutes, or until the crust is golden brown and the filling is bubbly.

Allow to cool to room temperature before slicing and eating.