1) Melt butter in a heavy skillet or Dutch oven.
2) Sautee onions and garlic until tender.
3) Stir in flour until combined.
4) Stir in cream, vermouth and lemon juice. Add cheese and stir until melted.
5) Season with salt, pepper and nutmeg.
6) Gently fold in crab.
Serve warm with crostini or crackers.
Yields 8 servings.