Cast Iron Fried Onion Hamburgers
Cook's Illustrated points out that this technique was pioneered to save meat during the Depression, but it's just too delicious to pass up! These make a great non-grill-requiring hamburger for colder winter months.
1 onion, halved and sliced thin
Salt and pepper
12 ounces 85 percent lean ground beef
1 tablespoon unsalted butter
1 teaspoon vegetable oil
4 hamburger buns, toasted
Combine onion slices and 1 teaspoon salt in colander and let sit for 30 minutes, tossing occasionally. Transfer to clean dish towel, gather edges, and squeeze onion slices dry.
Spread onion slices on rimmed baking sheet, sprinkle with ½ teaspoon pepper, and toss to combine. Divide onion mixture into four 2-inch mounds. Divide ground beef into 4 lightly packed balls. Place balls on top of onion mounds and flatten beef firmly so onion adheres and patties measure 4 inches in diameter.
Heat 12-inch cast-iron skillet over medium heat for 5 minutes. Add butter and oil and heat until butter is melted. Using spatula, place patties onion side down in skillet. Reduce heat to medium-low and cook until onion is deep golden brown and beginning to crisp around edges, 5 to 7 minutes.
Flip burgers and continue to cook until lightly browned on second side, about 2 minutes. Place on bun tops. Serve.