(this is for 1 sandwich)
1 slice of fresh mozzarella
1 slice of tomato
1/2 Shallot sliced
2 slices of bread, your choice on kind
2 Tbs butter
Start of with throwing your sliced shallots in a pan with a Tbs. of butter. You want to caramelize the shallots. Cook for a couple minutes and then flip them over to brown the other side. Once caramelized, take them out of the pan and set aside.
Take your bread and all your ingredients. Add 1 slice of mozzarella, 1 slice of tomato, then the caramelized shallots. Top with the other slice of bread and butter both outside pieces of bread well. Place into the already warmed pan.
I find that low and slow is the way to go with grilled cheese. If you cook them on too high of heat, the inside doesn't get warm enough. I also like to put a lid on them to make sure the insides get all nice and melty!
Cook until nice and brown. You want the outside to be crunchy!