Fry the meatloaf in a pan first. This gets it deliciously crispy and ensures it is heated through.
Butter outsides of bread slices with 2 tsp of the butter.
Add remaining 1 tbsp butter to the pan with the oil and swirl to melt.
Add the sandwich and cook over medium heat (not to hot or the bread will burn before the cheese melts).
Notes
Warm the meatloaf slice all the way through.Crisp up the meatloaf slice first so it holds a good structure and gives you great texture.Cook the sandwich on medium so that the cheese melts and to prevent the bread burning. Choose a melty cheese that isn't too strong in flavor.