Get everything ready so you're not scrambling (measure ingredients out, prep the ice water, cut the butter into 1/2 inch cubes, etc.).
In a food processor, mix the flour, 1 tablespoon of granulated sugar, and 1/4 teaspoon salt. Add the butter cubes and pulse until crumbs form. With food processor running on low speed, add the water and lemon juice through the spout on the lid. Stop processing once the dough just barely starts to clump together.
Transfer the dough to a large piece of cling wrap. Form the dough into a disc shape and cover with the plastic wrap. Refrigerate for 45 min - 1 hour.
When the dough is almost finished chilling, preheat the oven to 375F and move the rack to the bottom of the oven.
Prepare the filling by combining the filling ingredients in a medium bowl.
Dust a large piece of parchment paper with flour. Roll the dough out to a circle that's about 12" in diameter and 1/8" thick. Dough doesn't need to look perfect, and the edges will be ragged. Move the parchment paper with the dough on it onto a baking sheet.
Spoon the filling onto the middle of the galette. Leave a few inches along the edges. Fold the edges over, just barely covering the fruit filling.
Brush the edge of the galette with some water, and dust it (especially the edges) with the remaining tablespoon of granulated sugar. Bake for 30-35 minutes, or until the crust starts to brown and the filling is nice and bubbly.
Let it cool for 15 minutes prior to serving. Serve with ice cream or whipped cream if desired.