Simple Boiled Crabs with Garlic-Vermouth Butter

Combine the first 8 ingredients in a small skillet over medium-low heat. Cook, stirring occasionally, for 3 minutes or until the butter melts. Keep warm.Combine 6 liters of water, vinegar, and the following 3 ingredients in a large roasting pan. Bring to a boil over high heat.While the water heats up, put the crabs on a baking sheet with sides and put them in the freezer. (This makes crabs easier to cook - they should be well chilled, but not frozen; don't leave them in the freezer for more than 30 minutes.) When the water boils, grab each crab securely by the shell and gently but quickly lower it headfirst into the boiling water.Cover the pot and bring the water to a boil. Cook the Dungeness crabs for 18 to 20 minutes, and the blue crabs for 5 minutes. Drain, peel and serve with warm cream sauce.