Tomato Tart with Caramelized Onions, Olives & Anchovies

Directions

1. First, make the pastry for the tart crust. Combine flour, sugar, and salt in a food processor or medium bowl. Scatter the cubes of butter over the mixture and cut in until the butter resembles small pebbles. Sprinkle 3 Tbsp. cold water over the mixture and process or stir until the dough just begins to clump together. If it seems too dry, add more water, no more than 1 Tbsp. at a time, until it begins to stick together. Dump the dough clumps onto a clean countertop or board and quickly knead to form a cohesive ball of dough. Pat into a disk, wrap with plastic, and refrigerate for at least 15 minutes.
2. Caramelize the onions. Melt 1 Tbsp. butter in a wide sauté pan over medium-low heat. Add the sliced onions, season with a ½ tsp. kosher salt, and cook until dark and sweet, about 45 minutes, stirring periodically. When they are thoroughly caramelized, season with a few twists of black pepper, and allow to cool to room temperature before filling the tart shell.
3. While the onions are cooking, form the tart shell. Roll the tart dough into an 11 in. circle and transfer to a 9 in. tart pan with removable bottom. I like to roll the dough on a sheet of waxed paper or parchment to allow for a smoother transition. Press the dough into the pan and even the sides. Place in the refrigerator to chill for an hour or more.
4. Preheat the oven to 425°. If you have a pizza stone, preheat it to cook the tart on (this helps ensure a crisp bottom).
5. Fill the tart shell. Sprinkle the chilled shell with about ? of the grated fontina. Spread the onions over the cheese and top with another ? of the cheese. Layer the tomato slices, shingling slightly, as needed. Sprinkle the tomatoes with a little oregano and black pepper. Top with remaining cheese, olives, and anchovies.
6. Bake the tart on the hot pizza stone for 45-55 minutes, until the crust is golden and cooked through and the tomatoes are soft and tender. Remove from the oven and cool on a wire rack for at least 30 minutes before serving so the slices will hold together.