Heat the olive oil in a large pan over a medium heat.
Add the onion and cook for about 5 minutes until softened.
Add in the rice and cook for a further 3 minutes, stirring occasionally. Season to taste with salt and pepper.
Lower the heat and add in the vegetable stock 1 cup at a time, stirring frequently. Wait until all the stock has been almost absorbed into the rice before adding the next cup. Keep repeating the process for about 16-18 minutes, until rice is cooked.
Stir in the spinach and cook until warmed through. Remove from the heat and stir in the parmesan cheese.
Season to taste with a little more salt and pepper if necessary and serve immediately.
