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

Add the Arborio rice to the pan, stirring to coat the grains with oil for about 2 minutes.

Pour in 1 cup of warm vegetable broth and stir until the liquid is absorbed.

Continue adding the broth, one cup at a time, stirring frequently and allowing each addition to be absorbed before adding the next.

After about 15 minutes, add the asparagus pieces and continue cooking until the rice is creamy and al dente, about 5 more minutes.

Stir in the peas and grated Parmesan cheese, and season with salt and pepper to taste. Cook for an additional 2-3 minutes until heated through.

Remove from heat and let it sit for a couple of minutes before serving.