Caramelized Onion with shells

1 pound pizza dough store-bought or homemade, enough for 2 people, or as needed * 2 tablespoons olive oil 2 large red onions peeled, halved and thinly sliced[...]

3 x egg 1 c. lowfat milk 1 tsp Dijon mustard 1 pch salt and pepper 8 ounce grated cheddar cheese 8 ounce grated mozzarella cheese 4 x bacon , thickly sliced 3[...]