Adding onion delivers moisture; forming thicker patties prevents them from cooking too fast and drying out. Both steps are key when working with grass-fed ground beef.
1 small onion, coarsely grated
1½ pound grass-fed ground beef
1¼ teaspoon kosher salt, plus more
½ teaspoon freshly ground black pepper, plus more
1 tablespoon vegetable oil
Hamburger buns and desired toppings (for serving)
Using your hands, gently mix onion, beef, 1¼ tsp. salt, and ½ tsp. pepper in a medium bowl. Gently shape into four 1½”-thick patties (loosely formed patties will be more succulent).
Heat oil in a large skillet, preferably cast iron, over medium-high heat. Season patties with salt and pepper, place in skillet, and immediately reduce heat to medium. Cook 4–6 minutes per side for medium-rare. Serve on buns with desired toppings.
Patties can be formed 4 hours ahead. Cover and chill.