
Melt 1 tbsp butter in a large skillet over medium heat. Add thinly sliced onions with a pinch of salt and cook 12-15 minutes, stirring often, until soft and golden. Set aside.
Shape the beef into 4 thin oval patties roughly the shape of the bread. Season with salt and pepper and cook 3-4 minutes per side over medium-high heat until they reach 160°F. Wipe out the pan.
Build each sandwich: rye, a slice of Swiss, a patty, onions, another slice of Swiss, and rye. Butter the outsides.
Cook the sandwiches over medium-low heat 3-4 minutes per side, pressing gently, until the bread is crisp and the cheese is melted.
Slice in half and serve with dressing for dipping.
Photo: DinnerDrop