1 ½ lbs asparagus
4 Tbsp. unsalted butter
1 yellow onion, diced
3 garlic cloves, minced
¼ cup dry vermouth
3 cups chicken stock, plus more if needed
Salt and freshly ground pepper, to taste
¾ cup heavy cream
Snap off the tough stem ends from the asparagus spears. Cut the tips off 8 of the spears into 2-inch lengths. Set the tips aside. Chop the remaining asparagus into 1 inch pieces.
In a heavy soup pot over medium heat, melt the 4 Tbs. butter. Add the onion and garlic and sauté, stirring occasionally, until tender and translucent, 3 to 4 minutes. Add the vermouth and cook until most of the liquid has evaporated. Add the chopped asparagus and the 3 cups of chicken stock. Bring to a simmer, then reduce the heat to medium-low. Cover and cook until the asparagus is tender, about 20 minutes.
Using a blender, puree the soup until smooth, about 2 minutes. Pour back into pan and stir in cream plus more stock if needed to reach the desired consistency. Season with salt and pepper to taste. Set the pan over low heat and reheat the soup to serving temperature.
In a small sauté pan over medium heat, melt 2 tsp butter and add the reserved asparagus tips and cook until just tender, about 2 minutes. Ladle the soup into warmed bowls, garnish with the asparagus tips and serve immediately.