For the braised ox cheeks, place all the ingredients in a large bowl and marinade for 24 hours.
When marinated, put everything in a large saucepan and bring to a simmer. Skim off any impurities which rise to the surface.
Simmer for 2-2½ hours, or until the ox cheeks are tender. Leave to cool in the cooking liquor.
Once cooled, remove the ox cheeks from the liquor and strain the liquor through a fine sieve. Place the sieved liquor in a clean pan and bring to the boil. Reduce to a simmer and cook until the volume of liquid has reduced and the sauce has a glaze consistency. Keep warm until ready to serve.
For the horseradish pomme purée, blend the horseradish cream in a food processor for five minutes, then pass through a fine sieve.
In a pan of boiling salted water, cook the Ratte potatoes until they are tender. Drain and set aside to cool for a few minutes. When cool enough to handle, peel the potatoes and put them through a ricer. Stir in the butter, milk and horseradish cream to taste.
For the roasted bone marrow, preheat the oven to 180C/350F/Gas 4. Place the veal marrow bones on a baking tray and roast in the oven for approximately 12 minutes, or until the marrow reaches a core temperature of 70C/158F on a meat thermometer. Remove from the oven and set aside.
For the roasted carrots, put the chicken stock and 75g/2½oz butter in a saucepan and bring to the boil. Whisk to combine and season generously. Add the carrots and par boil. Add the remaining butter to a pan and heat until foaming. Add the carrots and cook until tender.
For the breadcrumbs, melt the butter in a frying pan until foaming. Add the breadcrumbs and fry until crisp and golden-brown. Add the thyme leaves, stir through and leave to drain on a plate lined with kitchen paper.
To serve, spoon the horseradish purée into a shallow serving bowl. Divide the ox cheeks among the bowls, placing it on top. Put the carrots and veal bones next to the ox cheek. Drizzle the sauce over and sprinkle with breadcrumbs.