Heat canola oil in a large skillet over MEDIUM heat. Add butter, brown sugar, and onions, tossing to coat. Sprinkle onions with salt and caramelize only stirring occasionally for 15-20 minutes. Cool completely.
In a mixing bowl, combine smoked Gouda, scallions, ½ cup of Adobo sauce, one diced chipotle pepper, and caramelized onions. Set aside.
Heat skillet again on HIGH heat. Add sliced steak and salt and pepper to taste. Saute steak, stirring frequently. About 2 minutes per side.
Spread the remaining 1 Tbsp. of butter evenly onto one side of the 12 slices of bread.
Heat pan to MEDIUM heat. Spread an even layer of cheese mixture on bread, top with sliced steak, and add another layer of cheese mixture. Close sandwich with another slice of bread. Toast on each side until bread is golden brown and cheese is melted. Slice in half and serve.
Nutrition information per serving: 500 Calories; 210 Calories from fat; 23.2 g Total Fat (9.4 g Saturated Fat; 5.8 g Monounsaturated Fat); 94.4 mg Cholesterol; 890.9 mg Sodium; 39 g Total Carbohydrate; 0.2 g Dietary Fiber; 39 g Protein; 4.4 mg Iron; 306.1 mg Potassium; 0.4 mg Thiamin; 0.3 mg Riboflavin; 11.2 mg Niacin (NE); 0.5 mg Vitamin B6; 1.3 mcg Vitamin B12; 4.1 mg Zinc; 25.8 mcg Selenium; 85.4 mg Choline.
This recipe is an excellent source of Protein, Thiamin, Riboflavin, Niacin (NE), Vitamin B6, Vitamin B12, Iron, Selenium, and Zinc. It is a good source of Choline.