Entree: Germany – Rhineland – Rheinischer Zwiebelkuchen (Rhenish savory onion tart topped with a creamy egg and bacon custard on a yeast crust)

Serving Size: 8

Approximate Time

Prep 1 hr 10 min

Cook 40 min

Additional 1 hr

Total 2 hrs 50 min

Ingredients

- For the dough:
- 1 cup (240 ml) warm milk (about 100–110°F / 38–43°C)
- 2 1/4 tsp (7 g) active dry yeast (1 standard packet)
- 1 tbsp (13 g) sugar
- 3 cups (360 g) all-purpose flour
- 1 tsp (6 g) salt
- 2 tbsp (30 g) unsalted butter, softened
- 1 large egg (for dough glaze), approx. 1.75 oz (50 g) (optional)
- For the filling:
- 2 lb (900 g) yellow onions, thinly sliced
- 6 oz (170 g) smoked bacon lardons, diced
- 2 tbsp (30 ml) butter
- 3 large eggs, approx. 5 oz (150 g) total
- 1 cup (240 g) sour cream (or Schmand/Crème fraîche)
- 1/2 cup (120 ml) crème fraîche or additional sour cream (optional for extra creaminess)
- 1 tsp (5 g) fine salt, or to taste
- 1/2 tsp (2 g) freshly ground black pepper
- 1/4 tsp (1 g) ground nutmeg
- 1 tsp (2 g) caraway seeds (optional, traditional)
- 2 tbsp (30 ml) vegetable oil (if needed)

Instructions

1. In a small bowl, combine warm milk, sugar, and yeast. Let sit 5–10 minutes until foamy to activate the yeast.
2. In a large bowl, combine flour and salt. Add the yeast mixture and softened butter; mix to form a soft dough. Knead 5–7 minutes until smooth and elastic. Cover and let rise in a warm place until doubled, about 45–60 minutes.
3. Meanwhile, heat butter in a large skillet over medium heat. Add the diced bacon and cook until it renders some fat and begins to brown, about 4–6 minutes. Add the sliced onions and a pinch of salt and cook slowly, stirring, until the onions are translucent and beginning to caramelize, about 25–30 minutes. If onions begin to stick, add up to 2 tbsp (30 ml) water or oil.
4. Drain excess fat from the onions and bacon mixture, reserving a little for flavor if desired. Allow the mixture to cool slightly.
5. In a bowl, beat the eggs with sour cream (and optional crème fraîche) until smooth. Stir in the cooled onion-and-bacon mixture, caraway seeds (if using), salt, pepper, and nutmeg. Taste and adjust seasoning.
6. Preheat the oven to 400°F (200°C). Grease a 10- to 11-inch (25–28 cm) tart pan or a rimmed baking sheet.
7. Punch down the risen dough and roll or press it into the prepared pan to form an even base with a slight rim. If desired, brush the dough with the beaten egg for a golden crust.
8. Pour the onion and custard mixture over the dough, spreading evenly. Bake in the preheated oven until the filling is set and the top is golden, about 30–40 minutes.
9. Remove from the oven and let cool a few minutes before slicing. Serve warm or at room temperature, traditionally with young wine (Neuer Wein) or a green salad.