Mix quark, cream cheese, yoghurt, milk and vinegar. Season with salt and pepper. Peel pumpkin, remove seeds. Cut the flesh into 1 cm thick slices. Cut out bones with a cookie cutter.
Cook the pasta in boiling salted water for 10-12 minutes. Add the pumpkin bones 3-4 minutes before the end of cooking time. Drain noodles and pumpkin and let them drain. Meanwhile clean and wash the peppers and spring onions.
Cut the peppers into very small cubes, spring onions into rings. Put some of both back for garnishing. Heat oil in a pan. Sauté the bell peppers and spring onions in it. Add noodles and pumpkin bones.
Season with salt, pepper and chili. Put the dip in a bowl. Garnish with chives and rest of paprika and spring onions. Arrange spaghetti on plates. Garnish with basil. Add dip.