Loaf of any type of bread (I use Brioche or potato)
Heat oven to 375 degrees.
Butter 6 slices of bread and set them on a large cookie sheet. Place slices of roast beef and cheese on all 6 slices and place in the oven for 7-8 min. Meanwhile, butter the other 6 slices of bread. Pull the partial sandwiches out and place the buttered bread on top(buttered side up). Place under the broiler on low for 3-4 min.
Enjoy right away or wrap in aluminum foil to take with you on the go. Refrigerate for leftovers.