Place the dish in the oven under the broiler for about 3-5 minutes until the cheese starts to melt; then remove from the oven and lower oven to 350 degrees F.
Next, add the mustard to the top half of each roll and place on top of the sandwiches.
1/3 Cup Spicy Irish Mustard
Melt the butter in a small saucepan on top of the stove and add poppy seeds; then brush on top of the buns.
4 Tablespoons Butter, 1 teaspoon Poppy Seeds
Bake for another 8-10 minutes until the cheese has melted and the tops are lightly browned.
Notes
To reheat, place on a cookie sheet, cover with foil and heat in a 350 degree oven for about 12 minutes.