1. Prepare Burger Patties: If using ground beef, roll into 2-3 inch balls, then smash flat into patties. Generously season both sides of each patty with 1/4 tsp each of salt, pepper, onion powder, and paprika.
2. Cook Burger Patties: Sear the seasoned patties on an oiled or buttered pan for 3-4 minutes per side for medium doneness, or 5 minutes per side for well done.
3. Make Mac Sauce: In a bowl, combine 1/4 cup mayonnaise, 3-4 tablespoons ketchup, 2-3 tablespoons yellow mustard, and 3-4 tablespoons buttered or sweet pickle juice (or sweet relish). Add 1/4 tsp each of pepper, onion powder, paprika, and a pinch of salt to taste. Mix well.
4. Prepare Grilled Onions (Optional): Sauté 1/2 diced onion and 2-3 minced cloves of garlic with 1/4 tsp each of salt, pepper, and onion powder on medium/medium-low heat until the onions are translucent and browned.
5. Prepare Truffle Fries: Cook 3-4 cups of frozen fries according to package directions (or prepare homemade fries). Once cooked, transfer to a large bowl and toss with 1/4 cup grated Parmesan cheese, 4-5 tablespoons truffle oil, 2 tablespoons dried parsley, and a pinch of salt and pepper to taste.
6. Assemble: Serve the cooked smashburgers on buns with Mac Sauce and grilled onions (if using), alongside the truffle fries.
