3 tablespoons olive oil, divided 1 large sweet onion, thinly sliced 6 sprigs fresh thyme, leaves removed and chopped 4 cloves garlic, finely chopped or grated 3 tablespoons balsamic vinegar Salt and ground black pepper ½ pound ground beef ½ pound ground pork 2 tablespoons unsalted butter, softened 8 thick-cut slices sourdough bread 1 ripe tomato, thinly sliced 12 basil leaves ½ pound ball fresh mozzarella, thinly sliced Mixed green salad, for serving

Share: