4 c. chopped yellow onions, about 4 lg. onions
8 tbsp. (1 stick) unsalted butter
2 qts. chicken stock
2 lbs. asparagus
1/2 c. buttermilk
Salt and freshly ground black pepper to taste

Melt the butter in a large pot and simmer the onions until very soft and golden, about 25 minutes. Stir often. Add the chicken stock and bring to a boil.

Meanwhile trim the tips from the asparagus and reserve. Cut about 1 inch from the butt ends. Add to the chicken stock the asparagus, simmer until soft.

Transfer the cooked asparagus and stock into a food processor or blender and blend until smooth. Pour into a large saucepan and add the buttermilk. Stir over low heat until blended. Salt and pepper to taste.