1. For the béchamel sauce, melt the butter in a small saucepan over medium heat. Add the flour and whisk continuously for 1-2 minutes until the flour is lightly cooked.

2. Gradually add the milk while whisking constantly to avoid lumps. Continue stirring until the sauce thickens. Finally, add the mustard, cinnamon, nutmeg, salt, pepper, and egg yolk. Mix well and remove from heat.

3. For the Croque Madame, lightly butter the slices of bread and toast them slightly in a pan or toaster. Then place one slice of mozzarella, one slice of cheddar, and 2 slices of bacon on one piece of bread.

4. Repeat the same for the other slice of bread, then stack them together. Top with the last slice of bread, spread the béchamel sauce on top, and sprinkle with some grated cheese.

5. Place in a preheated oven (180°) for 8-10 minutes until the cheese melts and turns golden.

6. Meanwhile, melt a little butter in a non-stick pan and fry the eggs sunny side up.

7. Serve the sandwiches warm with the fried egg on top. Sprinkle with freshly ground pepper.

Kali Orexi !