4 tablespoons good-tasting extra-virgin olive oil
1 large onion, finely chopped
1 cup grape tomatoes, halved; or 1 large ripe tomato, diced
Salt and freshly ground black pepper
2 large garlic cloves, finely chopped
1 pound ground turkey (organic, and half light and half dark meat if possible)
1/4 cup dry white or red wine
2 to 3 ounces extra-sharp cheddar cheese, cut into 1/4- to 1/2-inch cubes
4 large hamburger buns