In a bowl, crack and scramble one egg. Pour into one compartment of greased muffin tin or muffin top tin. Repeat for as many sandwiches as you'd like to make (ie if you only want to make 3 sandwiches, you'll only need 3 eggs).
Bake eggs at 350F for 10-13 minutes. The eggs will puff up quite a bit while baking, but they'll deflate as they cool.
While the eggs are baking, butter one side of each slice of bread. After the eggs have cooled, assemble sandwiches.
If you're planning to eat these fresh, grill them in a skillet on medium heat, just as you would if you were making a grilled cheese sandwich. Once the bread is browned on each side, it's ready to go! We love to add a little mayonnaise to ours to add just a little extra something to it.
If you want to premake them: grill them until the sandwich is just lightly toasted on each side and then remove from the heat. Allow the sandwiches to cool completely. Then wrap them individually in freezer paper, place in a large freezer bag together, and place in the freezer.
To prepare from freezer: place the sandwich in the refrigerator the night before. In the morning, remove it from the freezer paper, place it in the toaster oven on "toast" until it's heated through. Enjoy!