- 1/4 cup plus 1 tablespoon warm water (105°F to 115°F)
- 3/4 teaspoon active dry yeast
- 3/4 cup plus 2 tablespoons all purpose flour
- 3/4 teaspoon nigella (kalonji) seeds
- 1/2 teaspoon salt
- 1 tablespoon butter, room temperature
- 2 tablespoons extra-virgin olive oil
- 1 pound onions (about 2 medium), cut into 1/3-inch-thick wedges through root ends
- 2 teaspoons chopped fresh thyme
- 1 teaspoon honey
- 1 tablespoon Sherry wine vinegar
- 1/2 cup crème fraîche
- 1 large egg
- 1/2 teaspoon salt
- 1/4 teaspoon ground black pepper
- Semolina flour (pasta flour) or cornmeal
- 2 tablespoons chopped fresh chives
- Whisk 1/4 cup plus 1 tablespoon warm water and yeast in small bowl; let stand until yeast is dissolved, about 10 minutes.
- Mix flour, nigella seeds, and salt in medium bowl. Add yeast mixture and stir with wooden spoon until mixture clumps together. Add butter; mix until incorporated. Turn dough out onto lightly floured work surface and knead until smooth and elastic, about 5 minutes. Divide dough into 6 equal pieces; roll each into ball. Place on baking sheet; cover with plastic wrap. (Can be prepared 1 day ahead. Keep covered and refrigerate.)
- Heat oil in large nonstick skillet over medium-high heat. Add onion wedges to skillet and cook without turning until beginning to brown, about 7 minutes. Carefully turn onions over; reduce heat to medium and continue to cook until onions are tender and brown, occasionally stirring gently, about 10 minutes. Add thyme and honey; cook 1 minute. Stir in vinegar. Seasonto taste with salt and pepper. Remove skillet from heat. Cool. (Can be prepared 1 day ahead. Cover and refrigerate.)
- Let dough rise in warm draft-free area until doubled, about 1 hour. Whisk crème fraîche and egg in small bowl to blend. Stir in 1/2 teaspoon salt and 1/4 teaspoon pepper.
- Preheat oven to 450°F. Sprinkle 2 rimmed baking sheets lightly with semolina flour. Roll out each dough ball to 5-inch round. Transfer 3 rounds to each prepared baking sheet. Let rest 10 minutes. Pierce dough rounds all over with fork. Spread 1 generous tablespoon crème fraîche mixture over each dough round, leaving 1/4-inch plain border. Arrange onions evenly atop each; drizzle lightly with crème fraîche mixture (mixture may spill over edges of dough).
- Bake flatbreads until crusts are puffed and golden, about 12 minutes. Transfer to plates; sprinkle with chives.
- Available at some supermarkets, and at specialty foods stores and Italian markets.