1/4 teaspoon canola oil
5 ounces lean ground beef, divided into two 2 1/2-ounce balls
Salt and freshly ground black pepper
1 medium Vidalia onion, thinly sliced (about 1 cup sliced onions)
2 slices Sharp Cheddar cheese
2 soft hamburger buns
Mustard, pickles, and other condiments, if desired
Spread canola oil inside a large cast iron skillet with a paper towel. Heat over high heat until lightly smoking. Add balls of beef and press down with the back side of a spatula until completely flattened. Season generously with salt and pepper.
Spread onions evenly over cooking burgers and press down to embed onions into meat. Let cook with no further pressing until burgers are well browned, about 2 minutes.
Flip burgers with a stiff spatula. Let cook until onions start to soften, about 3 minute. Add cheese and top with top bun. Place bottom bun upside-down over top bun to allow it to steam in the onion vapors. When buns are soft, transfer bottom buns to a plate. Add condiments if desired. Lift up onions, burger, and top bun together and transfer to bottom bun.
