It was so good! I did it a little different than the recipe, so I will note my changes in bold. The original recipe is here, and I would take a look at it, because it shows the process step by step. Also, she helps you get the right bread (a good crusty artisan bread).
This was a HUGE hit here.
1 unsliced loaf of round bread
1 pound Monterey Jack cheese, thinly sliced (I used mozzarella because I had it, and also because I don't love monterey jack by itself)
1/2 cup butter, melted
1/2 cup finely diced green onion, including white part (I knew my kids wouldn't eat this if there was anything green, so I added some dried minced onions instead)
2-3 tsp poppy seeds
Directions: Using a sharp bread knife cut the bread going both directions. Do not cut through the bottom crust. Places slices of cheese between cuts. Mix together butter, onion, and poppy seeds. Pour over bread. Wrap in foil the entire thing in foil and place on a baking sheet. Bake at 350 degrees for 15 minutes. Unwrap. Bake 10 more minutes, or until cheese is melted.