Cook the pasta in salted water until al dente. Set aside.
Drain the canned white beans if there is any liquid. You won't need the liquid.Finely chop the parsley. In a deep frying pan, drizzle some olive oil and sauté the onion. Sprinkle in a tablespoon of flour and toast it briefly. Pour in 100 ml of water while stirring to thicken the mixture. Add the oat cream and mix well. Season with salt and pepper to taste.
Add the drained white beans and finely chopped parsley. Bring to a gentle boil, then mix the resulting ragout with the cooked pasta.