1. To prepare grinder, place feed shaft, blade, and 1/4-inch die plate in freezer 30 minutes or until well chilled. Assemble grinder just before grinding.
2. Arrange meat in a single layer on jelly-roll pan, leaving space between each piece. Freeze 15 minutes or until meat is firm but not frozen. Combine meat and oil in large bowl, and toss to combine. Pass meat through meat grinder completely. Immediately pass meat through grinder a second time. Divide mixture into 4 equal portions, gently shaping each into a 1/2-inch-thick patty. Press a nickel-sized indentation in the center of each patty. Cover and chill until ready to grill.
3. Preheat grill to medium-high heat.
4. Sprinkle patties with salt and pepper. Place on a grill rack coated with cooking spray; grill 2 minutes or until grill marks appear. Carefully turn patties; grill 3 minutes. Top each patty with 1 cheese slice; grill 1 minute or until cheese melts and beef reaches desired degree of doneness. Place 1 patty on bottom half of each bun; top each serving with 1 lettuce leaf, 1 tomato slice, and top half of bun.
Why Grinding's Good:
There's no question: Fresh-ground beef, lamb, or turkey yields a superior, juicier burger. That includes meat you've had ground to order in a butcher shop or at a supermarket and loosely wrapped (tight wraps compress the meat). At home, a grinder attachment for your stand mixer is ideal, or an old-fashioned hand grinder. Or you can use your food processor; in that case, be sure to work in small batches, pulsing the meat 8 to 10 times or until the meat is finely chopped but not pureed.
No matter what grinding tool you use, it's important to keep the meat and the grinding equipment as cold as possible. If the meat gets too warm, it will begin to smear rather than grind cleanly, giving the finished product a nasty mashed texture. Putting the meat and grinding equipment in the freezer for 15 minutes beforehand helps guarantee optimum results.
No time? In a pinch, you can of course use preground beef, lamb, or turkey for these recipes. The spices and condiments will still produce a better, lighter burger.