Roughly chop the walnuts. Heat 1 tbsp. oil in a frying pan and fry the walnuts for approx. 4 minutes, turning them over.
Peel and finely chop the onion. Clean, wash and thinly slice the fennel. Clean, wash and slice the red cabbage and cut it into slices
Mix orange marmalade, orange juice, diced onion, vinegar and 3 tbsp. oil. Season with salt and pepper. Mix fennel, walnuts, red cabbage and prepared sauce. Arrange on plates