To incorporate bourbon into your recipe, first create a béchamel sauce. Then, stir in a splash of bourbon to the cream sauce before you add in your cheese.
Incorporate your cheese in small handfuls and taste along the way, adding cheese and bourbon to taste. For more flavor, add more bourbon at the end once the cheese has melted.
However, note that bourbon is highly flammable, so never add it directly to a hot pan of oil. Instead, stir it slowly into the sauce, using a measuring cup to pour it.
Bourbon will pair well with pretty much any cheese — just make sure it's finely shredded for even melting. Sharp or white cheddar, gouda, or Jarlsberg would make a delicious fit.
While you'll want to save your best bottles for sipping, you should opt for a bourbon you enjoy. Options like Jim Beam, Old Crow, or Wild Turkey 101 would all mix well.
Bourbon also pairs well with rosemary, thyme, ground mustard, chill flakes, Cajun or Old Bay seasoning, onion, garlic, mushrooms, Worcestershire, or horseradish.