Mix all the filling ingredients gently and refrigerate until ready to use.
Now on a lightly floured parchment paper or a silicon mat, roll the dough into a 12 inch disc and transfer the disc on a baking sheet/pan. I used cookie tray here. Make enough room in your freezer, as we need to chill the shaped galette dough before baking.
Place the filling in the center (discarding the juices) of the disc leaving 2-3 inch border all around. Then fold the edges of disc over filling, overlapping the dough as necessary. Press gently to seal the edges.
Brush folded galette disc's edges with egg/milk wash and sprinkle it with coarse sugar. Chill the shaped galette for at least 20-25 minutes in the freezer or until the dough is firm to touch.
Preheat oven to 425°F (190°C). Bake galette the crust is golden brown and the filling inside in bubbly, about 30-35 minutes. Cool on the baking sheet for 10-15 minutes before slicing and digging in!