Steps
1. Preheat a skillet or griddle over medium heat.
2. Spread butter on one side of each bread slice.
3. In a small bowl, mix together Dijon mustard, mayonnaise, garlic powder, and paprika.
4. Place one bread slice, buttered side down, on the skillet.
5. Spread the Dijon mustard mixture on the unbuttered side of the bread.
6. Layer the cheeses evenly on top of the mustard mixture.
7. Place the second bread slice, buttered side up, on top of the cheese.
8. Cook the sandwich for 2-3 minutes on each side, or until the bread is golden brown and the cheese is melted.
9. Remove from heat and let the sandwich cool for a minute before slicing.
10. Serve hot and enjoy!