Whisk together the oat flour, millet flour, sweet rice flour, tapioca starch, sugar, xanthan gum, and salt in a large bowl.
Add the butter and mix with your hands, breaking up the butter until the largest pieces are about the size of an almond.
One tablespoon at a time, dribble in the ice water, combining each time, until the dough holds together when pinched with your fingers.
Roll the dough in a ball and flatten into a disc. Wrap with plastic and refrigerate for 30 minutes.
Preheat the oven to 400ºF.
Sprinkle some millet flour over wax or parchment paper, and roll out the dough over the paper until it’s about 12-14 inches in diameter. Optional: cut any jagged edges off for a smoother look.
Place the rolled-out disc of dough on a parchment-lined baking sheet.
Rosemary Pear & Concord Grape Filling
Begin by making rosemary sugar. Pulse the sugar and rosemary in a food processor until the lavender is finely ground. Alternatively mince the rosemary as fine as you can and blend it with the sugar by hand.
Arrange the pear slices fanned out in a single overlapping layer on top of the rolled-out crust, leaving a 2-inch border around the outside. Cover the top with the halved concord grapes.
Sprinkle half of the rosemary sugar over the fruit.
Gently fold the dough on the edges back over the fruit, pleating the edges as you go, leaving the center exposed. Use any dough you cut off to patch any holes.
Brush the edges lightly with milk and sprinkle the remaining sugar over the crust. Make sure you don't have any sugar on the pan surrounding the galette or it'll end up burning up (a little burnt sugar is totally normal, you'll be able to break it off and it won't impact your final flavor).
Bake until the the crust is golden brown and the fruit is bubbling, about 45 minutes.
Top with toasted pecans and serve with a slice of vanilla ice cream
Notes
*I grind my own oat flour by pulsing gluten-free rolled oats in a high-powered blender until completely fine.
This nutritional information has been automatically calculated, and as such, may be incomplete or inaccurate. Please reference the specific ingredients you use for the most accurate nutritional information.