Cook the Book: Sicilian Pizza

Name: Cook the Book: Sicilian Pizza
Ingredients: For the dough:; 3 cups all-purpose flour, plus more as needed; 2 1/4 teaspoons active dry yeast dissolved in 2 tablespoons of water; For the seasoning (the conza):; 3 medium onions, sliced; 2 tablespoons olive oil, plus more for the pan; 6 plum tomatoes, peeled; 2 garlic cloves; 6 anchovies, boned and chopped, or as desired; 1/2 pound cheese (caciocavallo or, in its absence, pecorino Romano) thinly sliced; 1 tablespoon chopped oregano; Salt