-
1
Place the trimmed, halved endives cut-side down in a wide, lidded pan. Add the 30 g butter, sugar, lemon juice, salt, and 3 tablespoons of water. Cover and cook over low heat for 30–40 minutes, turning once at the halfway point. The endives are done when a knife slides through the thickest part without any resistance and the cut faces are lightly caramelized.
-
2
Transfer the braised endives to a clean cloth. Press each half gently but firmly to expel all cooking liquid. This step decides the dish: any moisture left in the endives will thin the béchamel and prevent the gratin from setting — drain without compromise.
-
3
Melt the 50 g butter in a heavy saucepan over medium heat. Add the flour and stir continuously for 1–2 minutes to cook out the raw taste. Add the milk in a steady stream, whisking constantly. Cook, stirring, until the sauce is thick enough to coat the back of a spoon heavily and holds a clear line when a finger is drawn across it. Season with salt, white pepper, and nutmeg. Remove from heat and stir in 100 g of the grated cheese until fully melted and smooth.
-
4
Heat the oven to 200 °C. Butter a gratin dish. Wrap each braised, pressed endive half in one slice of jambon blanc and lay seam-side down in the dish, arranging the parcels in a single, close-fitting layer.
-
5
Pour the cheese béchamel evenly over the ham-wrapped endives, covering them completely. Scatter the remaining 100 g of grated cheese across the surface. Bake for 25–30 minutes. The gratin is ready when the surface is deeply golden and the béchamel is visibly bubbling at the edges — a pale top means the gratin is under-done.
-
6
Remove from the oven and rest for 2–3 minutes. Serve directly from the dish, scooping each portion to include endive, ham, béchamel, and a section of the golden cheese crust.