step 1
Add the All-Purpose Flour (1 1/4 cups), Salt (as needed), and Granulated Sugar (1 tsp) to a food processor. Add the Unsalted Butter (1/2 cup) and pulse until the butter is distributed into pea-sized pieces.
step 2
Add the Non-Fat Milk (1/3 cup) one tablespoon at a time, pulsing as you go, until the mix forms a rustic ball.
step 3
On a lightly floured surface, shape dough into a 5-inch disk. Wrap in plastic and refrigerate for 1 hour.
step 4
Preheat oven to 400 degrees F (200 degrees C).
step 5
On a floured board, allow dough to sit, unwrapped, until just pliable, about 15 minutes.
step 6
With a floured rolling pin, roll dough into a large circle, moving it a quarter turn with every roll to make sure it's not sticking underneath. In the end, dough should be 1/4-inch thick.
step 7
Ease dough round into a 9-inch tart pan with a removable bottom. Press tightly into the sides of the pan; the dough should exceed the edge by 1/2 inch. Using the rolling pin, cut excess dough against the tart pan to create a perfectly even edge. Chill 30 minutes before cooking.
step 8
With the tines of a fork, poke holes throughout the bottom of the crust.
step 9
Cover with foil and top with pie weights or uncooked beans or rice. Bake 15-20 minutes, or until edge of crust is light golden.
step 10
Remove crust from oven and carefully remove weights and foil. Return to oven to bake 5-10 minutes more. Cool on rack. Keep oven on at 400 degrees F (200 degrees C).
step 11
Add Olive Oil (2 Tbsp) to a saute pan and heat to medium-low heat.
step 12
Add the Onion (1) cook, tossing around every few minutes. Once the onions become translucent, reduce the heat to low. Cook 20-25 minutes until caramelized. Season the onions with Kosher Salt (1 tsp) and Freshly Ground Black Pepper (as needed). Set aside until needed.
step 13
Add the remaining Olive Oil (1 Tbsp) to a separate small saute pan. Cook the Garlic (2 cloves) and Fresh Thyme Leaves (2 tsp) until fragrant, about 30 seconds.
step 14
Add the Heavy Cream (1/2 cup). Increase the heat until mixture is reduced by half. Stir in Gruyère Cheese (3/4 cup).
step 15
Pour reduced liquid into prepared pie shell.
step 16
Top with onions and Beefsteak Tomato (1 cup), then sprinkle with remaining Gruyère Cheese (4 Tbsp). Cook until tart is hot and cheese is melted, 10-15 minutes.
step 17
Place under the broiler for 5 minutes before serving.
step 18
Garnish with Fresh Basil (to taste).
