Flemish Caramelized Onion Tart
Chef Mario Martinez
Rollin’ Oats Market & Café
At Rollin’ Oats Market & Café, chef Mario Martinez offers up a quiche-like tart that is versatile enough to go from brunch to supper. Caramelized onions and gruyere cheese infuse the dish with rich flavor.
3 cups all-purpose flour
1 tsp. kosher or sea salt
6 tbsp. cold butter, cut into small cubes
¼ cup rendered pork or bacon fat, chilled and cut into pieces
½ cup ice water
4 tbsp. butter, cut into chunks
3 lb. yellow onions, peeled, cored and julienned
Kosher or sea salt and freshly ground pepper, to taste
Freshly grated nutmeg, to taste
1 tsp. dried thyme leaves
2 large eggs
½ cup heavy cream
1 cup shredded gruyere cheese, divided
- Prepare tart shell: In food processor fitted with metal blade, combine flour and salt. Pulse once or twice to blend and aerate. Add butter and bacon fat; pulse until a coarse mixture forms. Gradually pulse in ice water until dough begins to stick together.
- Remove blade and gather dough pieces into a ball; do not handle too much. Wrap with plastic wrap, shape into a large disk and refrigerate 30 minutes.
- Preheat oven to 350 F. Remove the chilled dough; allow it to warm at room temperature for 5 to 7 minutes.
- On lightly floured surface, roll out dough to 14-inch diameter. Fold dough in half; place evenly on one side of greased and floured 10-inch tart pan. Gently unfold dough and carefully shape it evenly into pan. Run a rolling pin along edge around perimeter of pan to trim off excess dough. Line pie shell with fill and fill with dried beans or pie weights.
- Bake pie shell at 350 F. for 7 to 9 minutes or until parbaked. Cool on wire rack; remove weights and foil before assembly.
- Meanwhile, prepare filling: In 10-inch skillet over medium-high heat, melt butter until hot but not smoking. Add onions; saute 5 to 7 minutes or until they begin to brown. Reduce heat; continue cooking onions, stirring occasionally, for 15 to 20 minutes or until well-caramelized. Season onions to taste with salt, pepper and nutmeg; add thyme leaves and set aside to cool.
- In medium bowl, beat eggs and cream; stir in ¾ cup shredded gruyere and cooled onions. Pour mixture into parbaked crust; top with remaining ¼ cup cheese. Bake 35 to 40 minutes or until firm and golden.
Photo courtesy of National Onion Association