Name: The Ultimate Patty Melt Recipe with Caramelized Onions and Homemade Harissa Mayo
Prep time: 15 min
Cook time: 15 min
Ingredients: 800 g ground beef (1.75 lb); 2 medium onions (≈300 g); 4 tbsp butter (60 g); 2 tbsp vegetable oil (30 ml); 8 slices cheese (120 g, optionally 16 slices for double cheese); 8 slices bread; Salt; 1 large egg (50 g); 1 tbsp Dijon mustard (15 g); 1 tsp harissa (optional, 5 g); 200 ml neutral oil; Salt

Aller à la recette / Jump to recipe

If you love diner-style comfort food, the patty melt sandwich is an absolute must. Imagine juicy ground beef cooked to perfection, paired with sweet caramelized onions, gooey cheese, and crisp buttery bread. Now add a quick homemade mayo sauce with Dijon mustard and optional harissa for a spicy kick, and you have the ultimate comfort meal right at home.

This recipe is adapted from my original YouTube video, where I showed how to make a patty melt on a student budget. In today’s version, we’ll scale up to make four patty melts — ideal for family dinners, game nights, or sharing with friends.

If you enjoy recreating fast-food or diner classics at home, you’ll also want to check out my homemade Big Mac sauce, my hearty Salisbury steak, or my crispy Belgian fries.

Why You’ll Love This Patty Melt Recipe

Classic diner taste at home – cheesy, beefy, and perfectly toasted.
Budget-friendly – simple ingredients that don’t cost much.
Big-batch friendly – this recipe makes four sandwiches, but you can easily scale it down.
Customizable – swap cheeses, breads, or sauces for endless variations.

This patty melt also pairs beautifully with French classics like gratin dauphinois or Parisian potatoes.

Ingredients You’ll Need

For 4 patty melts:

800 g ground beef (≈1.75 lb)
2 medium onions (≈300 g), thinly sliced
4 tbsp (60 g) butter, divided
2 tbsp (30 ml) vegetable oil
8 slices cheese (≈120 g, Swiss, American, or cheddar – optionally double to 16 slices for extra cheesy melts)
8 slices rye bread or sandwich bread
Salt, to taste

And for the quick mayo sauce with harissa:

1 large egg (≈50 g)
1 tbsp Dijon mustard (15 g)
1 tsp harissa (optional, 5 g)
200 ml neutral oil (peanut, canola, or sunflower)
Salt, to taste

Step 1 – Make the Quick Homemade Mayo Sauce

Before starting the patties, whip up this immersion blender mayonnaise in under 20 seconds.

In a narrow container, add the egg, Dijon mustard, and optional harissa.
Pour the oil on top.
Insert the immersion blender and blend without moving for 8 seconds.
Slowly pull upward while blending to emulsify.
Season with salt.

👉 Spread a thin layer of this sauce on the inside of your bread slices before adding the patty and onions. It adds creaminess and a subtle heat.

Step 2 – Caramelize the Onions

Heat 1 tbsp butter + 1 tbsp oil in a skillet over medium heat. Add the onions with a pinch of salt and cook for 12–15 minutes, stirring often, until soft and golden. Set aside.

Love caramelized onions? Try them in my classic French onion soup.

Step 3 – Shape the Beef Patties

Divide the beef into 4 equal portions (200 g each). Shape each into thin patties roughly matching your bread size. Season lightly with salt.

Step 4 – Cook the Patties

In a skillet over medium-high heat, add 1 tbsp oil. Cook the patties for 4–5 minutes per side, until browned outside and medium doneness inside. Remove and rest briefly.

Step 5 – Assemble the Patty Melts

Butter one side of each bread slice.
On the unbuttered side, layer:
1. Slice of cheese (or two if doubling)
2. Beef patty
3. Caramelized onions
4. Another slice of cheese (or two if doubling)
Spread homemade harissa mayo on the inside if not already done.
Top with bread, butter side out.

Step 6 – Grill the Sandwiches

Heat a skillet or griddle over medium. Cook each sandwich until golden brown on one side (≈2 minutes). Flip and cook the other side until crispy and the cheese has melted.

Serving Suggestions

Patty melts go great with:

For dipping, try my homemade ranch dressing or even hollandaise sauce.

Variations

Spicy – add extra harissa or hot sauce.
French-inspired – spread with Roquefort sauce.
Vegetarian – swap beef patties for grilled mushrooms or plant-based patties.

FAQ

Can I make these ahead of time?
Caramelize the onions and shape the patties in advance, but assemble and grill right before serving.

What’s the best cheese?
Swiss is traditional, but cheddar, provolone, or American cheese all melt beautifully.

Can I cook them on a griddle?
Yes! Perfect if you want to make all four sandwiches at once.

Useful Links

🛒 Michel Dumas Shop : Explore our kitchen essentials, including aprons and knives.
🌐 Linktree : Access all our important links in one place.
📱 YouTube | Instagram | Facebook | TikTok : Follow us for the latest recipes and culinary tips.