Stuffed burgers grill in exactly the same way as conventional patties, but the preparation takes a little extra handiwork. Filling-wise, no combination of flavors seems to be off-limits, but certain food safety considerations apply where meat is concerned.
Using a mixture of ground beef and pork will give a patty that binds adequately without oozing excessive amounts of fat. Season the meat with salt and pepper and refrigerate for a short while, as cold meat is less sticky to work with. The patties should be brought to room temperature, however, before grilling. Without handling the meat more than necessary, which will result in a crumbly burger, form a regular-size patty and make a clear indent in the center, then fill it with the stuffing. Place another flat patty on top and press the edges of the two together to form a seal. While not necessarily quicker, dedicated burger presses allow for a larger cavity to fill, using a press to line a disc-shaped container with the ground meat, and a lid to seal the burger.
Turning a burger inside out is one of the first tricks to achieve with some adept stuffing, safe in the knowledge that cheese, onion and meat are a tried and tested combination. For a manageable, stringy center, use cubes or thin strips of Swiss, mozzarella, Gouda or cheddar cheese. Blue cheese or brie, on the other hand, afford the sensory pleasure of breaking into a viscous, oozing pocket of full-flavored melted cheese. Using a burger press allows more room for stuffing, in which case crumbled, crispy bacon or sauteed mushroom slivers can also join the cheese. Other fillings exploit sauces or chutneys for a burst of heat or sweetness in each bite. A fiery jalapeno tempered with sweet pepper stuffing, for example, saves the relish for the inside, whereas sweet blends of mango chutney or chopped pineapple lend a tropical theme.
The stuffed burger’s stint on the grill will cook the meat, melt cheese stuffing and sear the outside, but the grilling time is too short to cook through the ingredients in the stuffing. Although safely cooked, even the meat in the center of the burger can carry a pink tinge, but other raw meats such as bacon should never be used as a stuffing. Finely chopped raw onion worked into the meat mix prior to grilling boosts crunchiness, but aromatics should be sauteed first in oil and drained of excess liquid if the aim is to release their full sweetness and soften the texture. Bacon needs thorough cooking and chopping, while mushrooms must be sauteed to reduce their volume and moisten the flesh. Raw baby spinach or fine-shredded cabbage, by contrast, will wilt in the grill’s heat alone and can be added raw.
Once the burgers are at room temperature and ready to go on the grill, resist the temptation to goad them with excessive attention. Lay them on the grill and flip just once, allowing approximately 5 minutes on each side, and never attempt to flatten the patty with a spatula, which will squeeze out valuable juices and may even rupture the filling. Especially with a stuffed burger, allow the patty to rest after removing from the grill, not only because the meat continues to cook, but also to allow stuffings such as hot cheese to cool a little. Although the USDA recommends a safe internal temperature of 160 degrees Fahrenheit for ground meat, 165 F is the safer benchmark where stuffing is involved.