Blanch the savoy cabbage leaves in a saucepan with a little salt for about 5 minutes, rinse with cold water and remove the thick stems, then lay out overlapping on cling film.
Process 3 / 4 of the char, egg yolk, spices and cream into a fine farce. Pour the farce onto the savoy cabbage leaves and smooth out.
Then lay out the wild garlic leaves overlapping in the middle and place thin strips of the rest of the fish on top.
Then roll everything up tightly lengthways, like a strudel, so that there are no more air bubbles. Put in a terrine dish and place it in a sufficiently large casserole dish with a high rim.
Fill up to ¾ the height of the terrine dish with almost boiling water. Poach in the middle of the oven preheated to 100 ° C for 40-50 minutes.
Let the terrine cool down and carve it. It can be served lukewarm or cold.