- 1 package dry yeast
- 1 cup warm water
- 1 tsp honey
- 2 1/2 cups all-purpose flour
- 2 tsp salt, divided
- 1/2 cup plus 1 tbsp olive oil, divided
- 1 large onion, thinly sliced
- 1 medium tomato, cut into 1/4-inch slices
- 2 sprigs fresh rosemary, needles removed from stem
- 1/3 cup (packed) finely grated Parmesan cheese
- In a medium bowl, stir together yeast, warm water, and honey. Let rest until yeast blooms and bubbles form on top, about 10 minutes. Stir in flour, 1/4 cup olive oil and 1 teaspoon kosher salt. Turn the dough onto a well-floured surface and knead until dough is smooth, 5 to 10 minutes. Place dough in a lightly oiled bowl, cover with a kitchen towel or plastic wrap, and let rest in a warm place until dough doubles in size, about 1 hour.
- Preheat oven to 450 degrees F.
- Remove dough from bowl and press it into a lightly oiled 9- by 13-inch baking sheet until it touches the edges. Using your finger, poke holes all over the dough. Drizzle the dough with 2 tablespoons olive oil. Let rest until the dough becomes puffy, about 20 minutes.
- Heat 1 tablespoon olive oil in a large skillet set over medium heat. Add onion slices, cover and cook until onion is golden brown, stirring occasionally, about 20 minutes.
- Top the dough with tomato slices, caramelized onions, rosemary, Parmesan cheese, and salt. Drizzle with remaining 2 tablespoons olive oil.
- Bake until the focaccia is golden brown, about 20 minutes. Remove from oven and allow to cool on a rack. Cut into pieces and serve.