French onion tart
2 hrs 5 min
- 2 cups all-purpose flour
- 1/2 tsp salt
- 3/4 cup cold unsalted butter , cubed
- 1 tsp white vinegar
- 1 tbsp vegetable oil
- 1 red onion , sliced
- 4 shallots , peeled and sliced
- 1/2 tsp salt
- 1/2 tsp granulated sugar
- 4 eggs
- 1/2 cup 35% cream
- 1/4 cup milk
- 2 cups grated gruyère
- 1 tsp fresh thyme leaves
- WHIRL flour with salt in a food processor. Add butter and pulse until coarse crumbs form. Gradually add 1/4 cup ice water and vinegar, pulsing after each addition. Pulse just until dough starts to come together. Gather into a ball, then press into a disc. Wrap in plastic wrap. Refrigerate at least 45 min or up to 3 days.
- HEAT a large non-stick frying pan over medium. Add oil, then onions and shallots. Cook, without stirring, for 5 min. Reduce heat to medium-low. Add salt and sugar. Season with pepper. Cook, stirring often, until onions turn deep brown, 6 to 12 more min. Set aside.
- WHISK eggs with cream and milk in a medium bowl until smooth. Set aside.
- PREHEAT oven to 400F. Lay an 11-in. fluted tart pan on a baking sheet. Cut out a foot-long piece of parchment paper. Roll dough on a lightly floured surface into a 13-in. circle, about 1/4 in. thick. Carefully lift dough into tart pan. Gently press dough into the corners and up the edges of the pan. Trim and discard excess. Prick the dough with a fork about 15 times. Lay parchment on the shell and fill with 2 cups dry beans or pie weights.
- BAKE in centre of oven for 15 min, then cover with foil. Continue baking until shell is just golden, about 15 more min. Remove to a rack. Reduce heat to 350F. Lift out parchment and beans. Reserve beans for future use.
- SPRINKLE half of cheese, then onion mixture over warm crust. Add egg mixture. Sprinkle with remaining cheese, then thyme.
- BAKE in centre of oven until top is firm, 20 to 22 min. Transfer to a rack.Let tart rest 10 min before serving.
Pre-baking a tart shell or “blind baking” with dry beans or pie weights helps prevent the crust from shrinking or puffing up while baking.
Nutrition (per serving)
- 10 g,
- 26 g,
- 27 g,
- 2 g,
- 431 mg.