Wash half the thyme, shake dry and chop finely. Mix 1 tablespoon honey, vinegar and thyme. Season with salt and pepper. Wash the meat, dab dry and place in a bowl. Pour marinade over the meat.
Marinate for about 30 minutes.
Lentils in a sieve rinse and let drain. Put the lentils in a pot. Add 700 ml water and simmer at low heat for about 15 minutes. Wash the pumpkin, grate dry, cut in half, remove seeds and cut the flesh into slices.
Clean, wash and cut the celery into 1 cm wide pieces. Peel and halve onions. Drain the lentils. Mix pumpkin, celery, lentils and onions with 1 tbsp honey, remaining thyme and 1 tbsp oil and spread on a baking tray.
Season with salt and pepper. Cook in the preheated oven (electric cooker: 175 °C/ circulating air: 150 °C/ gas: see manufacturer) for approx. 35 minutes.
Heat 1 tablespoon of oil in a frying pan. Sauté the meat on both sides, turning it over. About 12 minutes before the end of the cooking time, place the meat on the tray. Remove the tray and arrange on plates.