A rustic German classic from the wine-growing regions, this savory tart pairs a thick layer of slow-cooked sweet onions and smoky bacon with a creamy custard over a tender yeasted crust. It's traditionally served warm with a glass of young new wine during the autumn onion harvest.
Prep Time25 mins
Cook Time55 mins
Total Time80 mins
Servings6
Yield6 servings
Nutrition Facts
Per serving (estimated)
- 560 kcalCalories
- 34 gFat
- 17 gSaturated Fat
- 48 gCarbs
- 4 gFiber
- 8 gSugar
- 18 gProtein
- 720 mgSodium
- 380 mgPotassium
- 120 mgCalcium
- 3 mgIron
- 10 mgVitamin C
- 210 mcgVitamin A
Ingredients
For the dough
- 2 1/4 cups (280 g) all-purpose flour
- 1 packet (7 g) active dry yeast
- 1 tsp granulated sugar
- 1/2 tsp fine salt
- 1/2 cup (120 ml) warm whole milk
- 3 tbsp unsalted butter, melted
- 1 large egg
For the topping
- 2 lb (900 g) yellow onions, halved and thinly sliced
- 6 oz (170 g) thick-cut bacon or speck, diced small
- 2 tbsp unsalted butter
- 1 tsp caraway seeds
- 1/2 tsp freshly ground black pepper
For the custard
- 3/4 cup (180 ml) heavy cream
- 1/2 cup (120 g) sour cream or quark
- 3 large eggs
- 1/2 tsp salt
- 1/4 tsp grated nutmeg
Directions
- Make the dough: stir yeast and sugar into the warm milk and let stand 5 minutes until foamy. Combine the flour, salt, melted butter, egg, and yeast mixture in a bowl and knead 8 minutes until smooth and elastic. Cover and let rise in a warm spot for 45 minutes.
- Roll the dough out on parchment into a 12-inch round and press into a 10-inch tart pan (or shape into a rectangle on a sheet pan), forming a raised edge. Prick the base with a fork and pre-bake at 400°F (200°C) for 8 minutes.
- Meanwhile, melt 2 tablespoons butter in a large skillet over medium heat. Add the diced bacon and cook 5 minutes until the fat renders. Add the sliced onions and a pinch of salt and cook, stirring often, for 20-25 minutes until deeply golden and softened.
- Scatter the caramelized onions and bacon evenly over the pre-baked crust, pressing gently to compact. Sprinkle with caraway seeds and black pepper.
- Whisk the cream, sour cream, eggs, salt, and nutmeg together until smooth. Pour slowly over the onions, distributing evenly.
- Bake at 400°F (200°C) for 28-32 minutes until the custard is set, puffed, and golden brown on top, and the crust edges are crisp.
- Cool in the pan for at least 10 minutes before slicing into squares or wedges. Serve warm.
- For the most authentic experience, pair with a mug of Federweißer (partially fermented new wine) and a simple green salad.
Cook’s Notes
- Use a mix of sweet Vidalia-style onions and yellow onions for the deepest flavor.
- Quark can be replaced with an equal amount of sour cream or full-fat crème fraîche if unavailable.
- The yeasted crust can be made a day ahead, wrapped, and refrigerated; let it come to room temperature before shaping.
- For a richer topping, scatter 1/2 cup crumbled bacon over the onions just before baking.
- Avoid overbaking; the center should still have a slight jiggle when removed, as it sets while resting.










