Christina's Cream of Asparagus Soup

1 1/2 lb. asparagus
4 Tbs. butter
1 yellow onion, diced
3 garlic cloves, minced
1/4 cup dry vermouth (optional)
3 cups chicken stock, plus more as needed
salt and freshly ground pepper, to taste
3/4 cup heavy cream

Snap off the tough stem ends from the asparagus spears. Chop the asparagus into 1-inch pieces.
In a heavy soup pot over medium heat, melt the 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 stock. Season with salt and pepper. Bring to a simmer, then reduce the heat to medium-low. Cover and cook until the asparagus is tender, about 20 minutes.
Using an immersion blender, puree the soup until smooth, about 2 minutes. Stir in the cream plus more stock if needed to reach the desired consistency. Season with salt and pepper. Set the pan over low heat and reheat the soup to serving temperature.
Ladle the soup into warmed bowls, garnish with the asparagus tips and serve immediately. Serves 4.