Blanch the sweetbread for 2 minutes in boiling water and then immerse in cold water.
Clean the sweetbread, remove the membrane with a knife.
Cut the onion, the carrot and the celery using a brunoise knife cut.
Allow the vegetables to 'sweat' in butter, add the sweetbread, add some white wine and allow to cook for 30 minutes at low heat, with the lid on.
Cut the forgotten vegetables in segments and blanch. Next, cook them in a little butter, a bottom of water, while adding some thyme and laurel.
Cook the vitelotte potatoes in salted water, with their skin intact. Next, peel the potatoes and crunch them, thereby adding butter, salt, pepper, and nutmeg.
Mix the bread crumbs with the crushed gingerbread and add the butter pomade. Next, roll out the paste between two sheets of greaseproof paper.
Brown the sweetbread, daub with the Onion Confit with Gingerbread, add the crumb bread paste and allow to gratinate in the oven.