Dab roast beef dry and cut the fat layer crosswise. Season with salt and pepper. Heat the lard in a roaster. First fry the roast beef on the fat side over a high heat for 3-4 minutes until brown, then turn and fry for another 3-4 minutes.
In the meantime, preheat the oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2). Crush the colored and black peppercorns together in the mortar. Spread them over the meat and press lightly. Bake in a hot oven for 30-40 minutes.
Clean or peel and wash the vegetables. Divide Romanesco into small florets. Quarter kohlrabi and cut into slices. Cover the vegetables and cook them in 1/4 l boiling salted water for about 8 minutes.
For the butter sauce, wash the herbs, dab dry and chop. Drain the vegetables, collect the vegetable water and measure 100 ml. Reduce by half with the wine in a small open pot over high heat.
Cut the butter into pieces and gradually stir it into the hot, but no longer boiling wine stock with a hand blender at very low heat, creating a creamy sauce. Season to taste with salt, pepper and sugar.
Stir in the herbs.
Wrap roast beef in aluminium foil and let it rest for about 10 minutes. Re-heat vegetables in the sauce. Cut roast beef into thin slices. Serve with vegetables and sauce. New potatoes taste good with it.