Prepare plates with flour, beaten eggs, and crushed panko breadcrumbs.
Coat each mutton chop in flour, egg, and then breadcrumbs, then set aside.
Boil 600ml of cream in a saucepan, season with salt and white pepper, and remove from heat.
Layer overlapping potato and turnip slices in an ovenproof dish, sprinkling garlic between layers.
Pour the warm cream over the vegetables and bake for 20 minutes.
Press the layers down with a fish slice and bake for another 10 minutes.
Continue baking until tender and golden, then let cool slightly.
Whisk duck egg, dijon, vinegar, salt, sugar, mustard powder, and paprika.
Slowly stir in olive oil to emulsify, then fold in cornichons, capers, and parsley.
Fry mutton chops in oil for 3 minutes per side, adding butter and lemon juice to baste.
Drain chops on paper and keep warm in a low oven.
Dry-fry mutton trimmings in a saucepan until the fat melts and bits are crisp.
Add onions and salt to the trimmings, cover, and cook until softened.
Stir in the cabbage and cook covered until wilted.
Serve two chops with cabbage, sauce gribiche, and a side of gratin.