To prepare the crust

1. In a bowl, combine almond meal, flour, and sugar. Using a pastry cutter or the back of a large fork, cut in the stick of butter until dough is uniformly pea-sized crumbles.
2. Lightly whisk the egg and extracts together in a separate bowl, and, using the pastry cutter again, combine the wet and dry ingredients. Only manipulate the dough as much as you have to to make it uniform. Overworking your dough will cause it to toughen when baked.
3. Place dough in the refrigerator for about ten minutes while you prepare your tart pan. Dough can also be left covered in the fridge at this point for up to one day.

When ready to prepare the tart

1. Preheat the oven to 350 degrees. Using your hands, butter a 9″ tart pan with a removable bottom with 1 teaspoon of softened butter. Lightly dust the bottom and sides of pan with flour.
2. Using your fingers, press the almond meal crust into the bottom and sides of the tart pan. You will likely use all but 3/4-1 cup of the dough. Trim any excess off the top.
3. Bake crust for 20-25 minutes, rotating halfway through, until edges are almost turning golden and the center crust is set. Allow to cool while you prepare your filling. Alternatively, the crust can be made one day in advance and set aside covered.
4. Bring a small-medium saucepan filled with an inch of water to a simmer over medium-low heat.
5. In a bowl just barely larger than the saucepan, whisk together the eggs, egg yolks, and sugar.
6. Once water is boiling, place the bowl of eggs on top of the saucepan and whisk until mixture becomes paler and slightly thickened, about 2 minutes.
7. Add the lemon juice and zest, continuing to whisk all the while. Occasionally turn your bowl to ensure you don’t cook the eggs. Continue whisking consistently until mixture is thickened, about the consistency of a very loose pudding. Your whisk should be leaving a momentary trail behind it as it moves through the bowl and the mixture should generously coat the back of a spoon. The entire cooking process will have taken about 10-12 minutes.
8. Turn the heat off, but with the pan still on the burner, add the cold butter, 1/2 tablespoon at a time, whisking until piece is combined before adding another piece. Stir in the vanilla.
9. Pour your filling into the tart crust. Place a piece of saran wrap directly on top of the filling and refrigerate for at least 2 hours. Tart is complete at this point, but lemon crumbs can be added as a garnish if desired.

To prepare lemon crumbs

1. Preheat oven to 350.
2. In a bowl, combine about 3/4 cup of reserved, uncooked almond tart crumbs with lemon zest and sugar. Drizzle in the melted butter and stir until small clumps form.
3. Spread out on a sheet pan and break up larger clumps to smaller, pea-sized pieces. Bake for 12-14 minutes, or until golden, shaking pan intermittently. Allow to cool. Sprinkle on top of tart or on top of each piece along with a generous dollop of sweetened whipped cream.