Begin by heating the veg stock in a saucepan. Once hot, reduce to a very low simmer (you want the stock to be hot as you add it to the risotto).
In a separate large pan, heat the oil on medium heat. Add the chopped onion and soften for 2-3 minutes, followed by the sliced mushrooms and chopped red pepper. Soften these for another 2-3 minutes, before adding the chopped garlic. Season with salt and pepper. Stir well and cook for 2 minutes, or until all the veg has started to soften.
At this point, turn up the heat and keep stirring the ingredients. Once the pan is very hot, add the risotto rice and stir constantly for a minute or so to avoid it catching on the bottom. The aim here is for the rice to start cracking and turning translucent, which will help it to absorb all the flavours from the liquid. Don't walk away from the pan – it's all hands on deck to keep stirring right now.
After a minute on high heat, add the white wine and lemon juice (but not the zest). If not using wine, replace this with 100ml of stock. The liquid will bubble vigorously at first, before calming down. Stir well for a minute and then reduce the heat.
Start to add ladles of the stock to the rice, stirring regularly. The idea is to 'beat' the rice to help release the starches and make it creamy. Don't drown the rice in stock, but also don't let it dry out too much. 'Sloppy' is the best word I can think of to describe it. The heat should be fairly low throughout, so that the rice is bubbling gently but not boiling.
Continue this process for around 15 minutes, before adding the nutritional yeast, lemon zest, spinach, halved cherry tomatoes, and plant-based milk. Stir well and cook for another five minutes, adding as much stock as you need to the pan. 1 litre of stock should be enough for 300g of rice, but add extra water if necessary. The spinach will wilt and the tomatoes will start to soften.
After the rice has been cooking for a total of 20 minutes, it should be 'al dente'. Each grain should be cooked through but still hold its shape. It may take longer than 20 minutes depending on how hot your stock is and how much you're cooking. Once the rice is creamy and cooked through, adjust the seasoning and then turn off the heat.
Optional step: At this point, I like to stir in a generous spoonful of plant-based butter and then cover with a lid. I find that this gives a nice gloss to the final risotto. After a couple of minutes, remove the lid and stir well.
Serve with a drizzle of extra-virgin olive oil and chopped fresh parsley or basil.