Ingredients:
1/4 teaspoon canola oil
5 ounces freshly ground beef, divided into two 2 1/2-ounce balls
Kosher salt and freshly ground black pepper
1 medium onion, thinly sliced (about 1 cup sliced onions)
2 slices American cheese
2 soft hamburger buns
Mustard, pickles, and other condiments, if desired
Directions: