A mouth-watering grilled cheese sandwich made with thick sourdough bread, butter, mayo, dijon, apples, gouda or white cheddar, and red onions. Perfect for a mid-day meal.
1: Preheat the oven to 350 degrees.
2: Heat cast iron skillet over medium heat. Warm pan with butter and add red onions.
3: Cook onions until they are golden brown and soften, but remain somewhat uncooked. Set aside.
4: Spread mayonnaise over inner sides of all 2 slices, then repeat with mustard on the other two. Layer cheeses evenly over the slices.
5: Choose one half of the sandwich and fan a stack of thinly cut apples and add a scoop of the cooked onions on top, closing the sandwiches with the other bread half.
6: In the same pan, heat the other 2 tablespoons of butter on medium heat. Add the sandwiches and toast each side of the bread about 4 minutes per side.
7: Finish in the oven to get that perfect gooey, melty finish or top the skillet with a lid to create a steam box to help melt the cheeses.
8: Cut in half and serve immediately or store in a sealed container in the refrigerator for up to 2 days.
