Melt 2 tablespoons of butter in a saucepan over moderate heat.
Add olive oil and stir.
Add the red onion and simmer until the onions sweat - approx. 3-5 minutes.
Stir in the arborio rice and toast, stirring constantly, for 3 minutes.
Add the beer, stir, and add 7 oz of the vegetable broth.
At this point, you're going to stir constantly for the next 10 minutes. The arborio rice will gradually soak in the liquids and become creamy.
After 10 minutes, add the mushrooms, asparagus, and the remaining 7 oz of liquid.
Stir constantly for another 10 minutes.
Once the 10 minutes is up, remove from heat.
Add 1 tablespoon of butter, asiago cheese, and stir to mix.
Cover for 3 minutes.