Copycat Steak ’n Shake Frisco Melt with Caramelized Onions

Why You’ll Love This Recipe

• Everything you crave from the classic Frisco Melt, made fully at home with everyday ingredients.
• Ultra-thin smashed patties for a deep, lacy crust and maximum beefy flavor.
• Sweet-tangy Frisco sauce and slow-caramelized onions bring diner-style nostalgia.
• Buttery grilled sourdough gives a crisp, shattering crunch in every bite.

Grocery List

• Produce: 2 large yellow onions
• Dairy: Unsalted butter, sliced American cheese, sliced Swiss cheese
• Pantry: Sourdough bread, mayonnaise, ketchup, sweet pickle relish, yellow mustard, distilled white vinegar, sugar, paprika, onion powder, garlic powder, Worcestershire sauce, olive oil, kosher salt, black pepper

Full Ingredients

Frisco Sauce

• 1/2 cup mayonnaise
• 2 tbsp ketchup
• 1 tbsp sweet pickle relish, drained
• 2 tsp distilled white vinegar
• 1 tsp yellow mustard
• 1 tsp granulated sugar
• 1/4 tsp sweet paprika
• 1/4 tsp onion powder
• 1/8 tsp garlic powder
• 1/2 tsp Worcestershire sauce
• Pinch kosher salt and black pepper

Caramelized Onions

• 2 large yellow onions (about 1 1/2 lb), halved and thinly sliced
• 1 tbsp unsalted butter
• 1 tbsp olive oil
• 1/2 tsp kosher salt
• 1–2 tbsp water (for deglazing, as needed)

Thin Smashed Patties

• 1 lb (454 g) 80/20 ground beef (chuck preferred)
• 1 tsp kosher salt (for seasoning patties)
• 1/2 tsp freshly ground black pepper
• 4 slices American cheese
• 4 slices Swiss cheese

Buttery Grilled Sourdough & Assembly

• 8 slices sourdough bread (about 1/2-inch thick)
• 3 tbsp unsalted butter, softened (for bread)
• Extra Frisco Sauce for spreading and serving

Step-by-Step Instructions

Step 1: Make the Frisco Sauce

In a small bowl, whisk together mayonnaise, ketchup, sweet relish, vinegar, mustard, sugar, paprika, onion powder, garlic powder, Worcestershire, and a pinch each of salt and pepper. Taste and adjust seasoning until sweet-tangy and balanced. Cover and refrigerate to let flavors meld while you cook (at least 15 minutes). Makes about 3/4 cup.

Step 2: Caramelize the Onions Low and Slow

Heat a large skillet over medium-low. Add butter and olive oil. Stir in sliced onions and salt. Cook, stirring every few minutes, until onions collapse, turn golden, and then deep mahogany, 30–35 minutes. If brown bits build up, splash in 1–2 tbsp water and scrape with a wooden spoon. The onions are ready when jammy, sweet, and richly browned. Keep warm over low or rewarm before assembling.

Step 3: Prep Bread and Heat the Cooking Surface

Butter one side of each slice of sourdough (these will be the outsides). Preheat a cast-iron griddle or heavy skillet over high heat for the burgers (surface about 425–450°F) and a second skillet or a cooler zone over medium heat for toasting the sandwiches.

Step 4: Portion and Smash the Patties

Divide ground beef into eight loose balls, 2 oz (57 g) each. Do not compact. Working in batches on the hot griddle, place 2–4 balls down, immediately top each with a small square of parchment, and press firmly with a stiff metal spatula to 1/8–1/4-inch thin. Peel parchment, season with salt and pepper, and cook 60–90 seconds until the edges are lacy and deeply browned.

Flip, then add 1 slice American to half the patties and 1 slice Swiss to the others. Cook 30–60 seconds more, just until cheese melts and the second side is browned. Stack an American-topped patty on a Swiss-topped patty to make four double stacks total. Cook ground beef to your preferred doneness (160°F center is the USDA recommendation).

Step 5: Sauce and Build the Sandwiches

Lay 4 slices of bread, buttered side down. Generously spread 1 1/2–2 tbsp Frisco Sauce on each. Add about 1/4 cup caramelized onions, then a double patty stack. Spread another spoonful of sauce on the top slices, then place them buttered side up.

Step 6: Griddle to a Buttery, Golden Crunch

Transfer assembled sandwiches to the medium-heat skillet or cooler griddle zone. Cook 2–3 minutes per side, pressing gently with a spatula, until the bread is deeply golden and crisp and the interior is hot and melty. Adjust heat as needed so the bread browns as the cheese stays oozy.

Step 7: Slice and Serve

Rest sandwiches 1 minute for the cheese to settle. Slice diagonally and serve with extra Frisco Sauce and any remaining caramelized onions on the side.

Pro Tips

• Use 80/20 ground chuck and keep the beef cold; colder meat smashes thinner and develops a better crust.
• Press hard in the first 10 seconds of cooking to lock in a lacy, deeply browned edge; do not press after flipping.
• Parchment squares prevent sticking and let you smash extra thin without tearing the meat.
• Cook onions patiently over medium-low; a splash of water clears fond without scorching.
• For perfectly even browning, use a two-zone griddle: high heat for patties, medium for the grilled sourdough.

Variations

• Spicy Frisco Melt: Add 1–2 tsp minced chipotle in adobo to the sauce and swap in pepper jack for the Swiss.
• Mushroom-Onion Melt: Sauté 8 oz sliced cremini with the onions during the last 10 minutes.
• Rye Patty Melt Twist: Swap sourdough for marble rye and toast with caraway butter.

Storage & Make-Ahead

Frisco Sauce keeps 7 days refrigerated. Caramelized onions keep 4–5 days refrigerated or 1 month frozen. Shape beef into loose 2-oz balls up to 24 hours ahead; keep covered and chilled. For best texture, assemble and griddle sandwiches to order. Leftovers can be reheated on a medium skillet 3–4 minutes per side or in a 350°F oven for 8–10 minutes; add a fresh swipe of sauce after reheating.

Nutrition (per serving)

Approximate: 900–980 calories; 34–38 g protein; 52–58 g fat; 60–68 g carbohydrates; 1,300–1,600 mg sodium. Values will vary with bread thickness and exact cheese/sauce amounts.