How to Make Stuffed Burgers
1. Make the patties.
Shape 1-1/2 lbs. of ground chuck (seasoned however you like) into eight 3-oz. portions on waxed paper. This is where a kitchen scale will come in handy. Press each portion into a 4-inch patty using a fork.
2. Top four of the patties with an onion slice and your favorite kind of shredded cheese.
Feel free to play around with fillings—try mushroom-Swiss, pico de gallo with pepper jack, or even jalapeno and blue cheese. Cover with the remaining patties, using waxed paper to flip each patty on top.
3. Seal the edges with a fork to keep all that melty goodness inside the burgers.
4. Grill the burgers over medium heat until they reach 160°.
This lets the filling heat through without the outside becoming overcooked. (If you're using ground poultry, make sure burgers hit 165° before pulling them off the grill.) Let the burgers rest for 5 minutes, just as we did with the burgers above. Then chow down.