Put the sausages in a frying pan with a little oil or fat and let them cook slowly over a low heat. Turn them as they colour, keeping the heat low, so they take on a sticky patina.
Cut the cauliflower into florettes, then into thin slices and place them in a bowl. Slice the radishes in half lengthways. Cut the carrots into long thin shavings with a vegetable peeler, then add to the cauliflower together with the radishes.
Finely shred the cabbage and combine with the vegetables. Pick the leaves from the parsley, dropping them into the vegetables as you go. Thinly slice the spring onions and the apple, then toss with the other ingredients.
Season the vinegar with salt and pepper. Remove the sausages from the pan and cut into thick slices then toss with the slices of vegetables and herbs. Pour the vinegar into the hot pan and let it bubble with the sausage fat for a few seconds then pour over the raw vegetables and sausages, toss lightly and serve.