Quick Recipe Version (TL;DR)
Quick Ingredients
- Dough: 2 1/4 cups (275 g) all-purpose flour; 1 tsp instant yeast; 1 tsp sugar; 1 tsp kosher salt; 2/3 cup (160 ml) warm water; 1 tbsp neutral oil
- Cream base: 3/4 cup crème fraîche; 3/4 cup full-fat sour cream (or fromage blanc); 1 tsp cornstarch; 1/4 tsp nutmeg; 1/2 tsp kosher salt; 1/4 tsp white or black pepper
- Toppings: 6 oz (170 g) bacon lardons; 1 large onion, paper-thin; 2 tbsp finely snipped chives
Do This
- 1. Mix dough: combine dry, add water and oil, knead 5 minutes; cover and rise 45 minutes.
- 2. Preheat a stone/steel at 500°F (260°C) for 45 minutes; rack in top third.
- 3. Slice onion very thin; mix crème fraîche and sour cream with cornstarch, salt, pepper, nutmeg.
- 4. Divide dough in two; roll each to 12 x 8 inches, almost paper-thin.
- 5. Spread a thin layer of cream base, then scatter onions and bacon lardons.
- 6. Bake 6–8 minutes until crisp with blistered edges; repeat with second tart.
- 7. Finish with chives, crack of pepper, slice, and serve hot.
Why You’ll Love This Recipe
- Ultra-thin, shatteringly crisp crust with smoky bacon and sweet, paper-thin onions.
- Restaurant-quality results at home using a blazing hot oven and a preheated stone or steel.
- Simple pantry-friendly dough; no complicated shaping.
- Perfect for sharing as a starter or pairing with a crisp salad for dinner.
Grocery List
- Produce: 1 large white or yellow onion, fresh chives (and optional fresh thyme)
- Dairy: Crème fraîche, full-fat sour cream (or fromage blanc)
- Pantry: All-purpose flour, instant yeast, sugar, kosher salt, neutral oil, cornstarch, white or black pepper, slab bacon (for lardons), nutmeg
Full Ingredients
For the Dough
- 2 1/4 cups (275 g) all-purpose flour, plus extra for dusting
- 1 tsp instant yeast (3 g)
- 1 tsp sugar (4 g)
- 1 tsp kosher salt (6 g)
- 2/3 cup (160 ml) warm water (about 105–110°F/40–43°C)
- 1 tbsp neutral oil (such as sunflower or canola)
For the Cream Base
- 3/4 cup (180 ml) crème fraîche
- 3/4 cup (180 ml) full-fat sour cream (or fromage blanc)
- 1 tsp cornstarch
- 1/2 tsp kosher salt
- 1/4 tsp freshly ground white or black pepper
- 1/4 tsp freshly grated nutmeg
For the Topping & Finish
- 6 oz (170 g) bacon lardons (from slab bacon, cut into 1/4-inch batons)
- 1 large white or yellow onion (about 250 g), sliced paper-thin
- 2 tbsp finely snipped fresh chives
- Optional: 1 tsp fresh thyme leaves; extra pepper for finishing
Step-by-Step Instructions
Step 1: Mix a quick, lean dough
In a medium bowl (or the bowl of a stand mixer), whisk the flour, instant yeast, sugar, and salt. Add the warm water and oil. Stir with a spoon until a shaggy dough forms, then knead by hand on a lightly floured counter for 4–5 minutes (or with a dough hook on medium speed for 3–4 minutes) until smooth and elastic. The dough should be soft but not sticky; add 1–2 tsp water or flour as needed to adjust.
Step 2: Let it rise briefly
Shape into a ball, place in a lightly oiled bowl, cover, and let rise at warm room temperature until slightly puffy and relaxed, about 45 minutes. This is a short rise; you do not need it to double.
Step 3: Preheat hot and high; prep toppings
Place a baking stone or steel on the top-third rack of your oven and preheat to 500°F (260°C) for at least 45 minutes. If you do not have a stone/steel, turn a sturdy baking sheet upside down and preheat it the same way.
While the oven heats, slice the onion as thinly as possible (a mandoline works well). Pat dry with paper towels. If your bacon is very fatty, you can briefly pre-render it: cook in a cold skillet over medium heat for 2 minutes just until some fat releases; drain on paper towels (do not fully crisp).
Step 4: Stir together the crème base
In a small bowl, combine crème fraîche, sour cream (or fromage blanc), cornstarch, salt, pepper, and nutmeg. Mix until smooth. Keep chilled until you’re ready to spread; a cool mixture helps the crust stay crisp.
Step 5: Roll the dough ultra-thin
Divide the dough in half. Working with one piece at a time on a sheet of parchment, roll into a rough 12 x 8-inch rectangle (or an oval), about 2 mm thick. Aim for even thinness; the edges can be a touch thinner to encourage blistering. Lightly dock the surface with a fork to prevent bubbles.
Step 6: Top and bake the first tart
Spread half of the cream mixture in a very thin layer over the dough, leaving a 1/4-inch border. Scatter with half of the onions and half of the lardons. Slide the parchment with the tart onto a pizza peel or upside-down baking sheet and transfer to the preheated stone/steel.
Bake 6–8 minutes until the edges are deeply golden and blistered and the bacon is rendered. If baking on a preheated baking sheet instead of a stone/steel, bake 9–12 minutes. Rotate once if needed for even browning.
Step 7: Finish, slice, and repeat
Transfer the tart to a board. Sprinkle with half the chives (and thyme, if using) and add a final crack of pepper. Slice immediately into squares or strips. Repeat Steps 5–6 with the second piece of dough and remaining toppings. Serve hot and crisp.
Pro Tips
- Heat matters: Preheat your stone or steel for a full 45 minutes at 500°F (260°C) for restaurant-level blistering.
- Keep it thin: Roll the dough to about 2 mm and spread only a whisper-thin layer of cream. You should see the dough through the onions.
- Dry ingredients = crisp crust: Pat onions dry and lightly pre-render bacon for 1–2 minutes to reduce excess moisture.
- Transfer with parchment: Build the tart on parchment for an easy slide onto the hot stone; it also prevents sticking.
- Slice onions paper-thin: A mandoline or very sharp knife makes translucent slices that soften quickly in the oven.
Variations
- Mushroom and Thyme: Add 1 cup very thinly sliced cremini mushrooms (well dried) with the onions; finish with extra thyme.
- Cheese-Lovers: Sprinkle 1/2 cup finely grated Emmental or Gruyère over the cream before the toppings for a richer, melty finish.
- Apple Sucré (Dessert): Swap bacon and onion for paper-thin apple slices. Keep the cream base, sprinkle with 1–2 tbsp sugar and a pinch of cinnamon, and bake until bubbled and golden.
Storage & Make-Ahead
The dough can be made ahead and refrigerated, covered, for up to 48 hours; bring to room temperature for 45–60 minutes before rolling. The cream base keeps in the fridge for 3 days. Slice onions up to 1 day ahead and keep wrapped and chilled. Baked flammkuchen is best fresh, but leftovers keep in an airtight container in the fridge for up to 2 days. Reheat on a preheated sheet or stone at 475°F (245°C) for 4–6 minutes to re-crisp, or in a dry skillet over medium heat. You can also freeze baked slices for up to 2 months; reheat from frozen at 475°F (245°C) for 6–8 minutes.
Nutrition (per serving)
Approximate for 1 of 4 servings: 700–760 calories; 45 g fat; 58 g carbohydrates; 22 g protein; 3 g fiber; 950 mg sodium. Values will vary based on bacon and dairy brands.
