In a saucepan, heat the vegetable broth and keep it warm over low heat.

In a large pan, heat the olive oil and butter over medium heat. Add the chopped onion and garlic, and sauté until the onion is translucent.

Add the Arborio rice to the pan and stir for 2-3 minutes until the rice is lightly toasted.

Gradually add the warm vegetable broth, one ladle at a time, stirring frequently. Allow the rice to absorb the broth before adding more.

After about 15 minutes, add the asparagus pieces to the risotto.

Continue adding broth and stirring until the rice is creamy and al dente, about 30 minutes total cooking time.

Remove the pan from heat and stir in the grated Parmesan cheese. Season with salt and black pepper to taste.

Serve warm.