Hard-Boiled Egg Gratin in a Bechamel Sauce

Hard-Boil the Eggs

1. Boil Water:
   • In a saucepan, bring salted water to a rolling boil.
2. Cook Eggs:
   • Carefully add the eggs to the boiling water. Reduce the heat to a simmer and cook for 10 minutes.
3. Cool and Shell:
   • Once cooked, transfer the eggs to a bowl of cold water until they are cool enough to handle.
   • To shell the eggs, gently roll them on a hard surface using the palm of your hand to crack the shell. Peel the eggs under a slow stream of running water to help remove the shell easily.
4. Reserve:
   • Place the shelled eggs in a bowl of warm water to keep them warm.

Prepare the Béchamel Sauce

5. Sauté Onions:
   • In a small saucepan or frying pan, melt a bit of butter over low heat. Add the chopped onion and cook, stirring frequently, until the onions are tender but not browned.
6. Make Béchamel:
   • In a medium heavy-bottomed saucepan, melt 2 tablespoons of butter over low heat.
   • Add 2 tablespoons of flour and whisk continuously for about 2 minutes, ensuring it does not color.
   • Gradually whisk in 2 cups of milk, bringing it to a boil while whisking constantly to avoid lumps.
   • Season the sauce with nutmeg, salt, and pepper to taste.
   • Reduce the heat and let the sauce simmer for 10 minutes, whisking continuously and scraping the bottom and sides of the pan to prevent sticking.
   • Stir in the cooked onions and cook for an additional 5 minutes.

Assemble and Cook

7. Preheat the Grill:
   • Heat the grill while you prepare the gratin.
8. Slice the Eggs:
   • Slice the hard-boiled eggs into 1 cm (0.4 inch) thick rounds.
9. Layer the Dish:
   • Spread a thin layer of the béchamel sauce over the bottom of a gratin dish.
   • Arrange the sliced eggs on top of the sauce, then cover with the remaining béchamel sauce.
   • Sprinkle grated cheese generously over the top.
10. Grill:
    • Place the gratin dish under the grill, adjusting as necessary to ensure even browning. Grill until the top is golden brown.
11. Serve:
    • Serve immediately while hot.