Grilled Cheese and Roast Beef Sandwich

Instructions

1. Prepare the bread
   Lay out the 4 slices of sourdough bread on a clean work surface. Spread the outside of each slice with softened butter, making sure to cover the entire surface evenly.
2. Add condiments and seasonings
   Flip the bread over and spread Dijon mustard on the inside of each slice. If using horseradish sauce, spread it on two of the slices. Sprinkle the garlic powder and black pepper evenly over the mustard.
3. Layer the sandwich fillings
   On two of the bread slices (mustard side up), layer half of the cheddar cheese, followed by the roast beef, red onion slices, Swiss cheese, and remaining cheddar. Make sure the fillings are evenly distributed.
4. Assemble the sandwiches
   Top each sandwich with the remaining bread slices, mustard side down and buttered side up, to create two complete sandwiches.
5. Grill the sandwiches
   Heat a large skillet or griddle over medium heat. Once hot, place the sandwiches in the pan and cook for 3-4 minutes on each side, until the bread is golden brown and crispy and the cheese is fully melted.
6. Rest and serve
   Remove the sandwiches from the heat and let them rest for 1 minute. Cut each sandwich diagonally and serve immediately while hot and cheese is still melty.