Melt butter (I used 2 slabs of buter, about a teaspoon) over medium heat on the stove. Place the bread and wait for it to begin to brown.
Meanwhile, slice your tomatoes as thinly as possible - we don't want a lot of juice to make our sandwiches soggy!
Pick up your bread and add more butter to the pan, then add the bread to your new melted butter, un-cooked side down. Add a few slices of Brie cheese to each piece of bread. I tried to slice mine really thin but it turned out more like chunks. If that happens, don't worry! Just try to spread it around on the bread so that the entire sandwich winds up being cheesy.
Add your ham and tomatoes, then put the sandwich together and press firmly with a spatula so that it "sticks together." I flipped mine a few times to make sure that it cooked evenly on both sides.