it's time to touch raw meat. First divide into 4 even peices. shape into 4 balls, then gently press each shape into 3/4 inch-thick patty-be sure not to overhandle/squeeze/smash it because it wil toughen. slightly flatten each patty a little more in the middle(they tend to plump in the middle as they cook). if the edges crack, press them back together.
Measure 1/4 tsp. of the salt, then pinch and sprinkle over the tops. then season the tops with 1/4 tsp. of the pepper (about 6 turns on a pepper mill) Turn the patties over and season the same way with the remaining1/4 tsp. salt and 1/4 tsp. pepper. refrigerate on a plae until you're ready to cook
Get your toppings ready.
Heat the broiler (with the oven rack about 4 inches from the top). Placeyour patties on a broiler pan or rimmed sheet pan and slide under the broiler. keep a close eye on them and cook until browned on the first side, 3 to 5 minutes. then flip (resist the urge to smash down the patties with your spatula) and cook another 3 to 4 minutes for medium. transfer to a plate to rest.
To heat the buns, split them open and place cut side up on a rimmed sheet pan and heat under the broiler. build your burger.