Step 1

For the dough:

Step 2

Dice butter and keep cold until ready to use.

Step 3

Place all dry ingredients in a food processor to combine. Add diced butter slowly, until the mixture forms a ball.

Step 4

Tightly wrap dough in plastic wrap and chill dough for at least 1 hour (the dough can be made in advanced and frozen until ready).

Step 5

Once ready to bake, preheat oven to 350 F and roll dough into one large pie or 4 to 5 individual rounds.

Step 6

Prick the pie crusts with the tines of a fork and transfer dough to pie tins. Line the pie dough with parchment paper (the paper should fit snugly on top of the dough itself) and fill with uncooked beans or pie weights.

Step 7

Blind bake pie dough for 12 to 15 minutes until golden.

Step 8

For the onion filling:

Step 9

Adjust oven rack to center position.

Step 10

Season onions with salt and let sit for 15 minutes.

Step 11

Melt butter and add olive oil in a large heatproof non-stick or cast-iron skillet over medium heat. Add onions and toss to coat.

Step 12

Transfer to oven and roast, tossing occasionally, until deeply caramelized and tender, about 30 minutes. Let cool on a sheet tray.

Step 13

For the pecorino fonduta:

Step 14

In a saucepan over medium heat, add cream and cook until reduced by about half.

Step 15

Transfer to a blender (or using a hand blender) and puree cheese and salt into the reduced cream while still hot. Set aside until you're ready to build your tart.

Step 16

To assemble:

Step 17

Fill cooled pie crust with roasted onions, completely covering the crust. Pour a thin layer of fonduta over the onions. Sprinkle with pecorino cheese.

Step 18

Place pies under the broiler to caramelize the cheese, 3 to 4 minutes.

Step 19

Garnish with cracked black pepper, a drizzle of aged balsamic and a sprinkle of thyme leaves. Serve hot or at room temperature.