This is definitely the perfect hangover breakfast (or maybe dinner depending on when you wake up and decide to eat). When I was a kid, my mom used to make this for us (note: we were not hungover at that time). If I recall her method correctly, the bacon was the top layer ... and only one side was cooked in a pan. The uncooked side was faced up and finished cooking under the broiler.
But I like bacon to be really crisp and the minute or so it takes to brown the cheese while under the broiler is not enough to get the bacon the way I like. So I fully cook the bacon before assembling.
Toast the bread. Top with warmed baked beans. Add a slice or some pieces of bacon, then the cheese. Bake in oven at 350 degrees F for about 5-8 minutes to get all of the ingredients hot. Then pop the broiler on high. Broil until cheese is brown and bubbly.