The Way to a Man's ♥~
Make sure they're big enough for the slice(s) of cheese to fit. If you notice, my front flat top burner (not turned on) makes a good measurement for the size of each patty.
Place the cheese slices (your favorite- doesn't have to be American, though that's what I used)
Sandwich the cheese between two patties and press edges together to form a seal.
I tend to "bake" my burgers these days on a lightly greased broiler pan rather than in the skillet where it tends to hold a lot of the greasiness.
I preheat my oven to between 400º and 425º and simply pepper the tops of the burgers, bake for approximately 10 minutes, flip/pepper them & bake another 10, flip again. With a plain burger, I can usually cook them within 30 minutes and add cheese slices at the very end. With the Juicy Lucys, I'd say it would be wise to go at least 40-45 minutes, to be sure the patties on both sides are fully cooked.
Top with another slice of cheese just before removing from oven and then whatever your favorite burger toppings after that.
Also wise is to give the burgers 5-10 minutes rest before biting/slicing into, as evidenced by my top picture- When I sliced into mine, it oozed EVERYWHERE! What a mess, but it was delicious!