Place butter and chopped onions in a medium pan (non-stick2) over low-to-medium heat. Cook for 5 mins, until the onions are soft.
Add risotto rice and toss around for 2-3 mins.
Add white wine3, and wait until it bubbles away (1-2 mins).
Add in the vegetable stock, a third at a time. Actively mix it until the liquids are mostly absorbed/evaporated each time (takes a couple of mins). After you add the last bit of the stock, toss in the asparagus4 and cover for about 5 minutes.
At this point the risotto rice should be super al dente (which I like). But if it's undercooked or too hard (taste it), add more hot water to the pan. You may need to add up to 100-150ml.
Once the rice texture is ready, mix in the spinach and cheese mixture, until evenly incorporated.
Season with salt and black pepper (taste it!)
This veggie risotto is good on its own, but also goes well if topped with smoked salmon or sun dried tomatoes (once plated).