Tarte Flambee

INGREDIENTS

• 1/2 teaspoon active-dry yeast
• 1/2 teaspoon sugar
• 1/2 cup plus 2 tablespoons warm water
• 1 1/2 cups all-purpose flour, plus more for work surface
• 3/4 teaspoon coarse salt
• Olive oil, for bowl
• 2/3 pound thick-cut bacon, cut into 1/2-inch pieces
• 2 large yellow onions, julienned
• Coarse salt and freshly ground black pepper
• 1/2 cup creme fraiche
• 1 large egg
• 1/4 teaspoon ground coriander
• 2 1/2 ounces Comte cheese, finely grated
• 1 tablespoon packed fresh thyme leaves, plus more for garnish
• 1 teaspoon creme fraiche
• Thyme leaves