Steps:

• "1. Combine onion and 1 teaspoon salt in bowl and toss to combine. Transfer to colander and let set for 30 minutes, tossing occasionally. Tsing tongs, transfer to clean dish towel, gather edges, and squeeze onion dry. Sprinkle with 1/2 teaspoon pepper. 2. Divide onion into 4 separate mounds on baking sheet. Form beef into 4 lightly packed balls and season with salt and pepper. Place beef balls on top of onion mounds and flatten firmly so onion adheres and patties measure 4 inches in diameter. 3. Melt butter with oil in 12-inch nonstick skillet over medium heat. Using spatula, transfer patties to skillet, onion side down, and cook until onion is deep golden brown and beginning to crisp around edges, 6-8 minutes. Flip burgers, increase heat to high and cook until well browned on second side, about 2 minutes. Place1 slice cheese on each bottom bun. Place burgers on buns, add desired toppings and serve."

Steps:

• "1. Combine onion and 1 teaspoon salt in bowl and toss to combine. Transfer to colander and let set for 30 minutes, tossing occasionally. Tsing tongs, transfer to clean dish towel, gather edges, and squeeze onion dry. Sprinkle with 1/2 teaspoon pepper. 2. Divide onion into 4 separate mounds on baking sheet. Form beef into 4 lightly packed balls and season with salt and pepper. Place beef balls on top of onion mounds and flatten firmly so onion adheres and patties measure 4 inches in diameter. 3. Melt butter with oil in 12-inch nonstick skillet over medium heat. Using spatula, transfer patties to skillet, onion side down, and cook until onion is deep golden brown and beginning to crisp around edges, 6-8 minutes. Flip burgers, increase heat to high and cook until well browned on second side, about 2 minutes. Place1 slice cheese on each bottom bun. Place burgers on buns, add desired toppings and serve."