Cheesy croissant hot dog: preheat oven to 450 F (205 C).

Add 1 teaspoon of vegetable oil to a parchment-lined sheet pan. Top the oil with 2 tablespoons diced onion and a pinch of salt, and pepper. 

Pile half of the shredded cheese on top of the onions and then squirt 1 tablespoon of mustard on top of the cheese.

Top everything with one of the sliced hot dogs.

REPEAT for your second hot dog.

Bake at 450 F (205 C) for 10 minutes until the cheese starts to get very melty.

Cut croissant dough to the correct size to cover your split hot dog. For me, that was about a 3 x 5-inch rectangle.

Whisk 1 whole egg with 1 tablespoon of water. This is your egg wash.

Top each sliced hot dog with a piece of croissant dough and then with a brush or spoon, paint the top of the dough with egg wash. Add poppy seeds or salt and pepper to season the dough if using.

Once both pieces of dough are in place and painted with egg wash, place the pan back into the oven and bake for an additional 10 to 15 minutes until the dough is golden brown and the cheese is starting to brown around the edges.

When they are done, carefully remove each hot dog to a rack or plate to cool. At this point you can top with whatever you want. But I chose to go Chicago-style.

Chicago dog assembly: Carefully remove the cheesy croissant dog from the parchment and flip it over so that the cheese is facing up.

Add tomato slices, one dill pickle spear, and 2 to 3 sport peppers to the top of each cheesy dog. Spoon a little relish on top and sprinkle the whole thing lightly with celery salt.

Serve and enjoy.