2 Tbsp unsalted butter
1 Tbsp canola oil
3 cups chopped onions
2 Tbsp finely minced garlic
6 cups defatted chicken broth
3 lb fresh asparagus
2 carrots, peeled and chopped
1 cup chopped flat-leaf parsley leaves
1 Tbsp dried tarragon
salt and pepper to taste
pinch of cayenne pepper
1/2 cup greek plain yogurt (or sour cream), for garnish
1 large ripe tomato, seeded and cut into small dice, for garnish
Melt the butter in the oil in a pot over medium-low heat. Add the onions and garlic; cook until tender, stirring occasionally, apprx 15 minutes. Add the broth, heat to boiling.
Trim woody ends off the asparagus. Reserve the tips, then cut the stalks into 1-inch pieces; add to the broth. Add the carrots, parsley, tarragon, salt, pepper, and cayenne to broth. Simmer, partially covered, until the vegetables are tender, apprx 45 - 50 minutes.
Puree with an immersion blender or in batches in a blender or a food processor, then strain soup back into the pot.
Before serving, add the asparagus tips and simmer over medium-low heat until the tips are tender and soup is hot, apprx 10 minutes.
Serve with a dollop of plain yogurt (or sour cream), if desired, and a sprinkling of diced tomato.