Blueberry Galette With Rosemary Crust

Preheat oven to 400u0b0 F
In a Kitchenaid mixer with the paddle attachment or a food processor, mix together the dry ingredients. Add the cubed butter and mix or pulse until butter breaks down into pea-sized pieces. If you don't have a stand mixter, you can use a pastry cutter, kitchen knives, or even (cold) hands to crumble the butter in the dough. Just try to work quickly if using your hands so the butter doesn't melt!
With the machine running or pulsing, add the ice water until the dough JUST begins to come together. Without the mixer, you can use your hands for this step.
Turn the crust mixture out onto some plastic wrap, then wrap it and flatten it into a disk shape. Refrigerate for about 10 minutes while you prepare the filling.
Throw all the filling ingredients into a bowl and mix well, so that that the sugar and flour coat all the blueberries.
Remove the chilled crust from the fridge and unwrap it onto a silpat or piece of parchment paper large enough to cover your baking sheet. Dust it with flour, then roll out the dough until it is between 1/8 and 1/4-inch thick.
Spoon the filling and its juices into the middle of the crust and spread it out, leaving a 2-inch border of crust. Fold the border of the crust over onto the filling, creating nice rustic edges.
Brush the crust with the beaten egg and sprinkle it with sugar. Slide the galette, still on the silpat or parchment paper, onto a baking sheet. Bake for about 40 minutes, or until crust is golden brown.