In heavy saucepan or stock pot over medium-high heat, add 3/4 pound butter, carrots, celery, onions, and garlic and cook until the vegetables have begun to brown, 10 to 12 minutes. Deglaze with the sherry, and stir and scrape up any bits. Once deglazed, add the flour and stir into the butter to create a roux. Once well mixed, add the stock and cream, reduce the heat to medium-low, and cook for 25 minutes, stirring throughout to ensure the soup does not scorch.
Pulse the soup with a hand mixer to mince the vegetables. Add the crab boil seasoning, crab roe, and parsley and continue to cook for 10 minutes. Remove the soup from heat, whisk in the remaining 1/4 pound butter, and stir in the crab meat.