For the Pie Crust:

1. In a large bowl, stir together the flour, salt, and sugar together.
2. Add the butter pieces and coat them with the flour mixture.
3. With a pastry blender, cut the butter into the flour mixture, working quickly until mostly pea-size pieces of butter remain. Be careful not to over blend the dough.
4. Combine the water, cider vinegar, and ice in a large measuring cup or small bowl.
5. Sprinkle 2 tablespoons of the ice water mixture over the flour mixture. Mix with a pastry cutter or spatula until the water is fully incorporated.
6. Add more of the mixture, 1 to 2 tablespoons at a time, using the bench scraper (or your hands) until the dough just comes together in a ball.
7. Squeeze and pinch with your fingertips to bring all the dough together, sprinkling dry bits with more small drops of the ice water mixture, if necessary, to combine.
8. Shape the dough into a flat disc, wrap in plastic, and refrigerate for at least 1 hour before using. 
9. The pie crust will last in the refrigerator for up to 3 days or the freezer for 3 months. If you’re using frozen dough, let it defrost in the refrigerator overnight before using.

For the Frangipane Filling:

1. Using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the frangipane ingredients (the butter, egg, almond flour, sugar, extracts, and rum, if using) in a medium bowl on medium-high speed until combined and creamy.
2. Cover and refrigerate until ready to use.
3. Frangipane can be stored in the refrigerator for several days. It also freezes well, just be sure to transfer it to the refrigerator in advance and allow it to thaw completely before using. 

For the Strawberry Filling:

1. Combine approximately 2/3 of the strawberries in a small pot.
2. Add the lemon juice and 1 to 2 tablespoons granulated sugar to taste (depending on the sweetness of the berries).
3. Cook over medium heat until strawberries start to break down and juices are thick and syrupy, about 10 minutes. Set aside and let cool.
4. The mixture can be stored up to 5 days in the refrigerator.

To Assemble:

1. Preheat oven to 400 degrees. Line a large baking sheet with parchment paper or a silicone baking mat and set aside.
2. On a lightly floured work surface, roll the dough into a 16-inch circle, and then transfer the dough to the prepared baking sheet.
3. Leaving a 3-inch border around the edges, spread the frangipane filling evenly over dough.
4. Next, using a slotted spoon, add the strawberry mixture over the frangipane, spreading it gently so it and frangipane remain in separate layers. Also, be careful not to overfill the galette (especially with the syrup). You don’t want the filling to overflow the crust or the galette to be soggy,
5. Fold the dough edges up over the filling, overlapping as necessary. About 6 to 8 inches of the filling should be exposed. Brush the crust edges with egg wash and sprinkle the crust with sliced almonds and coarse sugar, if using.
6. Refrigerate the shaped galette for at least 20 minutes and up to 8 hours (optional).
7. Bake until the fruit filling is bubbly and the crust is golden brown, about 35-40 minutes. Transfer to a wire rack to cool completely.
8. To serve, top with the remaining halved strawberries and dust with confectioners’ sugar if using. Add any additional toppings you like.
9. You can store any leftover galette in the refrigerator for up to 4 days