Flemish Caramelized Onion Tart
A terrific fall/winter meal to warm you up for a colder day. Chef Mario Martinez, corporate executive chef for Rollin’ Oats Market & Café in Florida, serves this up for friends and family at special gatherings. Chef Martinez says this dish pairs well with a red Burgundy or an Oregon Pinot Noir.
For the pie shell:
3 cups All-purpose flour
1 tsp. Kosher/Sea salt
6 tbsp. Cold butter, cut into small cubes
¼ cup Cold rendered pork/bacon fat or vegetable shortening, cut in pieces
½ cup Ice water
Aluminum foil, pie weights or dried beans (for blind-baking)
For the Tart:
4 tbsp. butter, cut into chunks
3 lbs. yellow onions, peeled, cored, and julienned
kosher/sea salt and freshly-ground black pepper, to taste
freshly-grated nutmeg, to taste
1 tsp. fresh thyme leaves
2 large eggs
½ cup heavy cream
1 cup shredded Gruyère cheese (Comté cheese is also commonly used)
Place flour and salt in a food processor fitted with a metal blade and pulse once or twice to blend and aerate. Add butter and shortening pieces and pulse until a coarse mixture is attained; gradually pulse in the ice water. Remove blade and gather dough pieces into a ball; do not handle it much. Wrap with plastic wrap, shape into a large disk, and refrigerate 30 minutes.
Preheat oven to 350ºF. Remove the chilled short-crust dough, allow it to warm at room temperature for 5-7 minutes, and roll-out to a 14-inch diameter. Fold the dough in half and place it evenly on one side of a greased and floured 10-inch tart pan. Gently unfold the dough and carefully shape it evenly into the pan. Run a rolling pin along the edge around the perimeter of the pan to trim-off excess dough. Bake the pie shell blind at 350ºF by lining with foil and filling with pie weights or dried beans for 7-9 minutes. Allow the par-baked crust to cool and remove beans or weights and the foil before tart assembly.
For the Tart:
Preheat oven to 425º F.
Heat the butter in a 10-inch skillet set over medium-high heat until hot but not smoking. Add the onions and sauté for 5-7 minutes or until they begin to brown. Reduce heat and continue to cook the onions, stirring occasionally, for 15-20 minutes or until well-caramelized. Season the onions to taste with salt, pepper, and nutmeg; add thyme leaves and set aside to cool. Mix the eggs and cream and all but ¼ cup of the cheese and add the cooled onions. Pour into the par-baked crust, top with the remaining cheese, and bake for 35-40 minutes.