Wash. trim your asparagus and then cut your asparagus into small strips, about 2 – 3 cm (0.78 inch – 1.18 inch) long.
In a wide medium sized saucepan, saute 2 tablespoons of butter, chopped onion, and sliced mushrooms over medium heat, until the mushrooms have reduced in size, onions are lightly browned, and most of the liquid is gone. This should take about 5 to 6 minutes.
Add the asparagus and cook for a further 1 to 2 minutes. See note 1.
Mix through the arborio rice and saute until lightly golden brown. This should take about 1 to 2 minutes.
Next, add the white wine and cook until almost all the liquid is gone from the saucepan.
Over low to medium heat, add about ½ cup (125 ml) of stock to the rice mixture. Gently stir the rice through the mixture constantly until almost all the liquid has absorbed.
Repeat until all the stock has been used up and the rice is soft and tender.
Remove rice from heat, mix through the grated parmesan cheese, remaining butter, and salt and pepper to taste.
Allow the rice to sit for 1 to 2 minutes with a lid on, then serve.