In a large pot, heat the olive oil on medium-high heat and sauté onion until translucent. Add the stock, asparagus, and basil. Bring to a boil, cover and simmer for another 20 minutes. Using an immersion blender, puree soup until smooth and creamy. Season with salt and pepper to taste.

*Create a pistou by blending basil, garlic and olive oil together. Drizzle on soup right before serving for an elegant finish.