Step 1

In a large skillet or grill pan over medium-high heat, melt 1 tablespoon butter; saute onion 6 to 8 minutes, or until it starts to brown. Remove to a bowl and cover.

Step 2

Shape beef into 2 oval patties; sprinkle with salt and pepper to taste.

Step 3

In the same skillet over medium heat, cook patties 5 to 7 minutes per side, or until no longer pink in center. Remove from skillet and keep warm.

Step 4

Spread remaining butter over one side of each slice of bread. Place in skillet buttered side down, and toast until lightly browned.

Step 5

To assemble a sandwich, place a slice of cheese on a piece of toast, top with a beef patty, half the onion slices, and half the salad dressing. Top with another slice of cheese and piece of toast; repeat with second sandwich, then serve immediately.