Recipe: Cardoons with Marrow Chef Patrick's Way

1 Blanch the cardoons (stems and hearts):
To do this, put the cardoons in a pot, cover them with cold water, add a few drops of lemon, salt, bring to a boil, then lower the heat.
Cooking: 1 hour 20 minutes at a gentle simmer, drain and set aside.

2 While cooking, in a pan that can go on the stove, arrange the marrow bone slices, cover them with cold water, salt and pepper, add a few drops of vinegar, a little thyme flowers and 1 bay leaf.
Bring back to a boil and lower the heat to minimum.
Cooking: 10 minutes. Turn off the heat and leave them in the cooking liquid.

3 At the same time, melt a little butter in a small pot, then slowly melt the sliced onions, add a splash of soy sauce, salt (lightly) and pepper, then let it sweat covered for 20 minutes.

4 Preheat the oven to 355°F (180°C) (gas mark 6).
In a pot, heat the béchamel, add the liquid cream.
Carefully remove the marrow slices and place them on a plate.

5 Then, in a deep oven-safe dish, pour the well-drained cardoons, give it a good grind of pepper mill, spread the onion mixture over it, and place the marrow slices slightly pressed in.
In the hot béchamel, quickly whisk in the egg yolk, then coat the dish with it, place it in the middle of the oven for 20 minutes normally.
This dish is exceptional to taste.
Of course you can prepare all of this in stages the day before: then all that remains the same day is to coat the dish with the heated béchamel and put it in the oven.