French Onion Soup Grilled Cheese

one of Top Chef judge Tom Colicchio's sandwich'es from his Wichcraft restaurant. Add lettuce, spinach or anything else you like but its great plain. caramelizing the onions takes time but worth it. (you can also do a double batch and freeze half for another time)

• Ready In: 40 mins
• Serves: 4

Ingredients

• 8  slices  aged gruyere cheese (minimum)
• 8  slices  rye bread, with caraway seeds
• 1  large Spanish onion, sliced thinly lengthwise
• 1  tablespoon olive oil
• 1  tablespoon butter
•  salt and pepper

Directions

1. Over a medium-high flame, heat the oil and add the onions. Cook them slowly (make sure the heat is high enough that they don’t steam) and allow them to gently caramelize, about 30 minutes. Add salt, pepper, and the butter at the end to season.
2. Assemble the sandwich. On a slice of rye, layer cheese, onions, and a second layer of cheese. Cover with the second slice of rye. Place on a panini grill and press. Sandwich is ready when the cheese has melted.