1. Chop onion and schallots, garlic and parsely. Add to saucepan with butter and saute until soft.
2. Add flour to form a roux and slowly add milk/cream mix on low heat with constant stirring until slightly thick.
3. Add flaked crab to mixture and half the cheese. Continue stirring until combined and add to vol au vent.
4. Sprinkle with additional cheese and bake in 200C oven for ~10 mins or until cheese is slightly browned