Clean, wash, peel and slice the beetroot. Peel and finely chop the onion. Peel the grapefruit so that the white skin is completely removed. Remove the fillets with a sharp knife between the parting skins.
Squeeze the juice from the membranes and collect it in a bowl.
Pour the beans into a sieve, rinse with cold water, drain well. Peel garlic and chop very coarsely. Heat 1-2 tablespoons of oil in a frying pan, add beetroot and cook over a low to medium heat for 6-8 minutes, turning.
Sprinkle with 1/2-1 tbsp. sugar, deglaze with vinegar, bring to the boil briefly and braise over a low heat for about 2 minutes. Season with salt and pepper and remove from the heat.
In the meantime heat 3 tablespoons of oil in a frying pan and fry the onion until transparent. Add beans, heat briefly. Season with salt and pepper. Carefully mix in grapefruit, deglaze with grapefruit juice, heat briefly.
Season to taste with salt, pepper and sugar. Remove from the stove.
Wash the meat and dab dry. Heat 2-3 tablespoons of oil in a pan and fry the meat on each side for about 2 minutes. Add garlic shortly before the end of the frying time. Place the meat on a baking tray lined with baking paper.
Spread garlic on the meat. Cook in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for 6-8 minutes.
In the meantime, roughly chop the pistachios. Put the pistachios and 3-4 tablespoons of oil into a small tall mixing bowl. Puree finely with a blender. Wash parsley, shake dry, pluck leaves from the stalks and chop finely.
Remove the meat from the oven, cover and let it rest for 2-3 minutes. Mix bean-grapefruit vegetables with beetroot, drizzle with some pistachio oil and sprinkle with parsley. Cut the meat into slices and arrange on plates with some vegetables.