Step 1: Make the Homemade Teriyaki Sauce
This sauce is the heart of the recipe. In a small saucepan, combine the soy sauce, ¼ cup of water, brown sugar, mirin (or rice vinegar), sesame oil, grated ginger, and minced garlic. Bring the mixture to a simmer over medium heat, stirring occasionally to dissolve the sugar. While it’s heating up, whisk together the 1 tablespoon of cornstarch and 2 tablespoons of cold water in a small bowl until a smooth slurry forms. Once the sauce is simmering, slowly whisk in the cornstarch slurry. Continue to simmer for another 2-3 minutes, stirring constantly, until the sauce has thickened enough to coat the back of a spoon. Remove from the heat and set aside. The sauce will continue to thicken slightly as it cools.

Step 2: Prepare the Pineapple and Onions
If using a fresh pineapple, cut off the top and bottom. Stand it up and carefully slice away the tough outer skin. Lay it on its side and cut it into 8 rings, about ½-inch thick. Use a small circular cookie cutter or a paring knife to remove the tough core from each ring. If using canned pineapple rings, simply drain them and pat them very dry with a paper towel. This is crucial for getting a good sear on the grill. Set the pineapple rings and sliced red onion aside.

Step 3: Form the Burger Patties
Gently place the 2 pounds of ground chuck in a large bowl. Sprinkle the salt and pepper over the meat. Using your hands, mix the seasoning into the meat as gently and as little as possible. Overworking the meat will result in tough, dense burgers. Divide the meat into 8 equal portions (about 4 ounces each). Gently form each portion into a patty that is slightly wider than your buns (they will shrink during cooking). Press a shallow dimple into the center of each patty with your thumb. This simple trick prevents the burgers from puffing up into a dome shape on the grill, ensuring they cook flat and evenly.

Step 4: Prepare and Preheat the Grill
Preheat your grill to medium-high heat, around 400-450°F (200-230°C). Clean the grill grates well with a wire brush to prevent sticking.

Step 5: Grill the Burgers and Pineapple
Place the burger patties on the hot grill. Cook for about 4-5 minutes per side for a medium-rare to medium burger. Try to flip them only once to develop a good crust. During the last 2 minutes of cooking, brush the tops of the burgers generously with your homemade teriyaki sauce. Place the pineapple rings and red onion slices on the grill alongside the burgers. Grill the pineapple and onions for 2-3 minutes per side, or until they have nice char marks and are tender. If you’re adding cheese, place a slice on each burger during the final minute of cooking and close the grill lid to allow it to melt perfectly.

Step 6: Toast the Buns
No great burger is complete without a toasted bun. During the last minute of grilling, place the buns, cut-side down, on the cooler part of the grill. Toast for 45-60 seconds until they are golden brown and warm.

Step 7: Assemble the Masterpiece
It’s time to build your burger. Spread a thin layer of mayonnaise on the bottom toasted bun, if using. Place a leaf of lettuce on top. Add your perfectly cooked, teriyaki-glazed burger patty. Top with a warm, caramelized grilled pineapple ring and a few rings of grilled red onion. Place the top bun on, and serve immediately.