Steam and roll the endive
Wash the endive and trim a small piece off the tough base. Steam the spears in a steam oven or steamer until tender. Let them cool and carefully squeeze out all the liquid so the sauce doesn’t become too watery later. Roll each spear in a slice of cooked ham and arrange the rolls in a baking dish.
Make the mashed potatoes
Cook the potatoes until tender and mash them with the butter and egg. Season with nutmeg and let the mash cool slightly. Fill a piping bag fitted with a large star tip with the mashed potatoes.
Prepare the béchamel sauce
Melt the butter in a large pot. Add the flour all at once and cook briefly. Add a large splash of milk and whisk vigorously until you have a smooth, thick sauce. Gradually add the rest of the milk, stirring constantly until the sauce is smooth and well bound. Season with salt, pepper, and nutmeg, then stir in most of the cheese so it melts.
Assemble the casserole
Pour the cheese sauce over the endive rolls in the baking dish. Sprinkle the remaining cheese over the sauce. Pipe the mashed potatoes along the edges of the dish using the piping bag.
Gratinate
Place the baking dish in a preheated oven at 190 °C for about 30 minutes.
Serve
Remove the dish from the oven and serve immediately, so the cheese sauce stays creamy and the mashed potatoes retain their beautiful texture.
Tips
- Let the endive drain well after steaming to prevent the sauce from becoming watery.
- Gently warm the milk for the sauce before adding it to avoid lumps.
- If you don’t have a piping bag, you can spoon the mashed potatoes in small mounds along the edge of the dish.
- Use a mix of cheeses (e.g., young + semi-aged) to add extra depth to the cheese sauce.
- Serve with a fresh green salad or roasted vegetables to provide some contrast.
