In a bowl, combine the cheese and tequila; let sit until the tequila is absorbed, about 45 minutes, gently tossing with a fork now and then.
Roast the peppers directly over a gas flame or under a preheated broiler, turning, until charred all over. Peel, seed and stem the peppers, then cut into 1/4-inch dice.
In a medium skillet, melt the butter. Add the onion and cook over moderately low heat until softened, about 7 minutes. Scrape the onion into the infused cheese. Add the mayonnaise, peppers, paprika, cayenne and mustard powder. Season to taste with salt and liquid smoke.
Keywords: Alcohol, Appetizer, Bell Peppers, cheddar, Cheese, Food & Wine, Hot Peppers, Jalapeno, Mayonnaise, pimento cheese, Spreads and Dips, tequila