Tuna w/Onion Confit

Ingredients

• 3 tablespoons extra virgin olive oil
• 3 large or 4 or 5 medium onions, peeled and thinly sliced
• Salt and freshly ground black pepper
• 1 large thyme sprig or 1 bay leaf
• 2 medium tomatoes, cored
• 1-1/2 to 2 pounds tuna, cut into steaks or left whole
• About 1/2 cup pitted and roughly chopped black olives