Classic American Diner-Style Patty Melt with Caramelized Onions

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · Published 2026-05-13 · Updated 2026-05-13

A nostalgic diner favorite featuring a juicy beef patty topped with melted Swiss cheese and sweet caramelized onions, sandwiched between buttery toasted rye bread. This american-inspired sandwiches & wraps ready in about 40 minutes pairs ground beef (80/20), salt, black pepper for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 650 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 1 lb ground beef (80/20)
• 1 tsp salt
• 1/2 tsp black pepper
• 4 tbsp, divided unsalted butter
• 1 large, thinly sliced yellow onion
• 8 slices rye bread slices
• 4 slices Swiss cheese slices
• 2 tbsp, optional yellow mustard

Instructions

1. Step 1: Heat 2 tbsp unsalted butter in a skillet over medium-low heat. Add 1 large thinly sliced yellow onion and cook, stirring occasionally, for 20 minutes until deep golden and caramelized. Remove onions and set aside.
2. Step 2: In a bowl, combine 1 lb ground beef with 1 tsp salt and 1/2 tsp black pepper. Form into 4 evenly sized patties about 1/2 inch thick.
3. Step 3: Heat the same skillet over medium-high heat and add the beef patties. Cook for 3-4 minutes per side until browned and cooked through. Remove from skillet.
4. Step 4: Spread 1/2 tbsp unsalted butter on one side of each of the 8 rye bread slices. On the non-buttered side, spread 2 tbsp yellow mustard on 4 slices if using.
5. Step 5: Assemble each sandwich by placing one cooked beef patty on the mustarded side of 4 bread slices, topping each with 1 slice Swiss cheese and a generous spoonful of caramelized onions. Top with remaining bread slices, buttered side out.
6. Step 6: Heat 1 tbsp unsalted butter in the skillet over medium heat. Add sandwiches and cook 3-4 minutes per side until bread is golden brown and cheese is melted, pressing gently with a spatula.