3 cloves garlic
1/2 cup extra-virgin olive oil, plus more for brushing
2 to 4 anchovy fillets, chopped
Juice of 1 lemon
Kosher salt and freshly ground pepper
1 pound skin-on, boneless chicken breasts
4 (1/2-inch-thick) slices focaccia or whole-wheat Italian bread
4 romaine lettuce hearts, halved lengthwise
3/4 cup freshly grated parmesan cheese, plus more for garnish