In a pan , heat 2 tbsp olive oil. Add the garlic cloves and chopped onions. Sauté till translucent. Add the chopped pumpkin, chili flakes and herbs. Cool till soft. Add salt and the skimmed milk. Let it boil till the pumpkin is really soft. Blend it till it's almost smooth. Meanwhile boil the pasta of your choice in a pot till aldente. Add the pasta to the sauce and serve warm garnished with chopped walnuts and coriander leaves.