The Basic Design

• Panini makers are designed primarily to make the pressed, toasted Italian-inspired sandwiches that give them their name. While grilled sandwiches are usually cooked in butter, which adds fat and calories, panini makers yield hot and tasty sandwiches, no butter required. They're outfitted with deeply grooved cooking surfaces on top and bottom, each with its own heating elements. Contact grills -- used for cooking meats and vegetables -- are very similar, and panini makers can usually do double duty as a grill.

A Few Things to Check

• Before you start slapping frozen patties onto your panini maker, especially if you haven't grilled on it before, take a few minutes to read the user's guide. Some work poorly as grills, lacking a tray to catch the drippings from your cooking meat. Others, especially those with ceramic grill plates, specifically forbid cooking frozen foods. The preheated grill plates might crack or shatter from thermal shock when they come into contact with the frozen patties, just as heated glass ovenware shatters if it's placed on a cold counter. If you don't have your user's guide, check the manufacturer's website or call its customer service line.

Fast and Easy

• If your frozen hamburger patties came from the supermarket, preparation is easy. Preheat your panini maker to a medium-high setting -- each model is different, so use your judgement -- and arrange the patties evenly over your cooking surface. Lower the lid so it presses gently on the patties, but doesn't exert any downward force. The lids of most panini machines can be adjusted for height, to make this easier. Standard 1/4-pound patties, approximately 1/4-inch thick, usually cook in five to six minutes. Thicker patties can take longer. Test one by sliding an instant-read thermometer horizontally into the burger, to ensure it has reached a food-safe temperature of 160 degrees Fahrenheit.

Homemade Patties

• If you make up your own patties and freeze them, that can present a few minor complications. The most important is that handmade patties tend to be somewhat variable in thickness, which means some might be pressed firmly against the upper cooking surface while others barely reach it. To ensure even cooking, press your patties carefully before freezing them. Place pieces of 1/4-inch square dowel on either side of your cutting board, then use the bottom of a baking sheet to flatten them to the same height. Use a larger dowel for thicker burgers. Thick burgers take longer to cook, often eight to 10 minutes, so be patient and use your thermometer to be certain. The cooking time recommended for frozen chicken breast is usually a good benchmark.