hamburger buns, split, Optional toppings: Tomato slices, lettuce leaves, dill pickle slices, ketchup and mustard. Season ground
beef with a dash of pepper and salt. In a food processor, pulse mushrooms until finely chopped. Gently but completely stir in the
seasoned beef. Form into four patties that are 1/2 inch thick. Heat two tablespoons of butter in a big pan over medium heat. Add
the burgers and cook, basting often with butter, for 6 to 8 minutes on each side, or until a thermometer registers 160°. Take
off the heat and remain toasty. Toast the bread tops in the pan until they get golden brown. Slide burgers onto bottom of buns. Place a tsp of butter on each. Swap out the bun toppers. Add toppings and serve.