Ham & Cheese Croissant Sandwich Recipe

Prepare croissants

Slice each croissant horizontally through the middle using a serrated knife so top and bottom halves remain intact.

Make spread

In a small bowl, mix the mayonnaise and Dijon mustard until smooth. Spread about 1/2 tablespoon of the mixture on the inside of each croissant half (both top and bottom).

Assemble fillings

Place 1 slice of Swiss cheese on the bottom half of each croissant. Fold or stack 2 slices of deli ham on top of the cheese (for a total of 2 slices ham per sandwich). If using tomato, add 1–2 thin slices on top of the ham. Add baby spinach leaves if using. Sprinkle a pinch (~1/4 tsp) of freshly ground black pepper over the fillings.

Finish assembly

Place the top half of the croissant over the fillings to close the sandwich.

Preheat skillet

Heat a large nonstick or cast-iron skillet over medium-low heat. Add 1 tablespoon of butter and 1 teaspoon olive oil (the oil helps prevent burning).

Brown croissant sandwiches

Place assembled croissant sandwiches seam-side down in the skillet. Press gently with a spatula. Cook 2–3 minutes until the bottom is golden and crisp. Carefully flip and cook another 1–2 minutes to warm through and lightly toast the other side. If cheese hasn't fully melted, cover the skillet for 30–60 seconds to trap heat and encourage melting.

Oven option

Alternatively, preheat oven to 350°F (175°C). Place assembled sandwiches on a baking sheet, dot tops with a little of the additional butter if desired, and bake 6–8 minutes until warmed and cheese is melted.

Remove sandwiches from heat and let rest 1 minute. Slice each sandwich in half on a diagonal if desired. Serve immediately while warm.