INGREDIENTS: 4 tablespoons olive oil, divided, plus more for drizzling 2 ounces pancetta (Italian bacon), finely chopped 4 garlic cloves, 2 thinly sliced, 2 whole 1/2 medium sweet onion, finely chopped 1/2 small fennel bulb, finely chopped, plus 1/4 cup fennel fronds 2 wide 3-inch …