The Bojon Gourmet

Make the crust:
2 Position a rack in the lower third of the oven and preheat to 350º.
3 In the bowl of a food processor, process the almonds, powdered sugar, salt and flour until the almonds are finely ground. Add the butter, and pulse until the mixture just begins to clump together. Dump the crumbs into an 8 or 9-inch tart pan with a removable bottom. Don't bother washing the food processor bowl. Press the dough into the sides of the pan first, then the bottom, taking time to make square corners, a neat top, and an even thickness. (If the dough becomes soft or sticky, put the whole pan in the refrigerator for 5-10 minutes to firm it up again.) Prick the bottom of the crust all over with a fork. Freeze the crust until firm, 15 minutes, or wrap for longer storage.
4 Place the tart pan on a rimmed baking sheet for easy maneuvering, and bake the unlined crust until it is pale golden, 15-20 minutes, rotating after 10 minutes for even browning.
Meanwhile, make the filling:
7 Toss the sliced rhubarb with 2 tablespoons of the sugar in a medium bowl and set aside to macerate while you finish baking the crust and making the custard.
8 Place the butter and vanilla pod and scrapings in a medium, heavy-bottomed saucepan and cook over medium heat, swirling occasionally. After about 5-10 minutes, the butter will foam up, turn golden and smell nutty, with brown flecks mingling with black vanilla bean seeds. At this point, remove the pan from the heat. Remove the vanilla bean (you can rinse and dry it and stick it in a jar of sugar, or use it to make vanilla extract). Pour the butter into a heatproof measuring cup to stop the cooking, and let cool 5 minutes.
9 In the bowl of the food processor, pulse together the remaining 1/2 cup of sugar, the flour and salt to combine. Add the eggs, and process until combined. With the motor running, pour in the brown butter, including the brown flecks and vanilla seeds, then the bourbon.
Assemble, bake, and eat the tart:
12 Scrape the rhubarb and any juices into the hot, par-baked tart shell in an even layer. Carefully pour the custard over the rhubarb, filling the shell to the brim.
13 Bake the tart until the filling is puffed and browned, 30-45 minutes, rotating the tart halfway through for even baking. Remove the pan from the oven and let the tart cool until warm. Set the tart on an inverted bowl or ramekin, and ease off the ring. Sprinkle the tart with powdered sugar, cut it into wedges, and serve warm or at room temperature.
14 The tart keeps well in the refrigerator for several days; re-warm slices in an oven or toaster oven for best results.