Let’s get started! Preheat your oven to 375°F (190°C). Preheating is essential. It allows the muffins to rise perfectly and develop a lovely golden color.

In a saucepan over medium heat, melt the unsalted butter. Once melted, sprinkle the flour in, whisking continuously to avoid lumps. Keep whisking for about a minute until it’s a smooth paste. Gradually pour in the warm milk, all the while whisking to mix thoroughly. Add the smoked paprika, Dijon mustard, freshly grated nutmeg, salt, and pepper to taste. Let it simmer until the sauce thickens slightly—about three minutes should do it. Finally, stir in the Gruyère or aged Comté cheese until it melts into a velvety texture.

Grease your muffin tin with some melted unsalted butter. This step is crucial. Nobody wants their delicious creation stuck to the pan.

Take your crustless bread slices and roll them out flat with a rolling pin. Next, cut them into a size that fits your muffin tin cups. Lay the pieces into the tins, pressing them down gently. These will be your muffin bases.

Sprinkle diced ham evenly into each muffin cup. Don’t hold back on this. The salty goodness will seep into every bite, enhancing that lovely flavor.

In a mixing bowl, whisk together the eggs, a little bit of salt, and half of your chopped parsley. Pour this mixture into each muffin cup, filling them generously, but don’t overflow.

Now, it’s sauce time! Drizzle your creamy cheese sauce over each muffin cup. Feel free to do this generously! Sprinkle extra cheese on top for that glorious cheesy finish.

Pop your muffin tray in the preheated oven. Bake for about 20-25 minutes, or until the tops are golden and slightly puffed. The aroma will be irresistible.

Once they’ve baked to perfection, allow your croque monsieur muffins to cool for a few minutes before removing them from the tin. Expert tip: a slight nudge with a knife around the edges can help release them if they’re feeling sticky.