- 2 tablespoons balsamic reduction, such as Rachael Ray brand or reduce 1/3 cup balsamic with 1 tablespoon light brown sugar
- 1 cup good quality organic ketchup
- 2 tablespoons olive oil, plus some for drizzling
- 2 large onions, sliced
- Salt and pepper
- 1 1/2 pounds 85% lean ground beef
- 1/4 cup chianti or dry red wine
- 2 large cloves garlic, grated or finely chopped
- 2 tablespoons rosemary, finely chopped
- 2 tablespoons sage, thinly sliced
- Sliced young pecorino, Gruyère or Fontina val D’Aosta, for topping
- 4 5-inch squares focaccia, split horizontally
Combine balsamic reduction with ketchup and set aside.
Heat a skillet with 2 tablespoons olive oil, 2 turns of the pan. Add onions and season with salt and pepper. Cook over medium low heat to caramel-colored and very sweet, 25-30 minutes, stirring occasionally. Add a touch of water to the pan to keep onions moist.
Preheat a cast-iron skillet or griddle over medium-high heat.
In a bowl, combine beef with wine, garlic, rosemary, sage, salt and pepper. Form 4 patties that are thinner at the center and thicker at the edges for even cooking. Drizzle patties with olive oil and cook 8 minutes, turning once. Top with cheese and melt under dome or tin-foil tent the last minute of cooking time.
Serve burgers on focaccia topped with caramelized onions and a little balsamic ketchup.