Add 1 tablespoon butter and olive oil to a large saute pan over medium-high heat. Once butter foams add the onion and saute until tender and soft, about 6 minutes.
Season the onion with salt and pepper. Add the rice and cook while stirring, until you can hear the rice crackle softly, and it becomes translucent around the edges. Add the wine and cook, while stirring, until the wine is almost dry and absorbed.
Once wine has been absorbed, add 1 cup hot broth at a time, stirring until almost all the liquid is absorbed, and then adding more. Cook until the rice is tender, about 25 to 30 minutes.
Stir in the blanched asparagus and peas. Cook until the peas are very bright green and the asparagus is warmed through. Remove from heat and add the remaining 1tablespoon butter and the finely grated Parmesan.