Add vegetable oil and spring onions to a large frying pan and cook on medium to high heat for a few seconds.
Add the rice and cook for 1 minute on low heat, stirring constantly until the rice looks glossy but not brown.
Add the garlic and mushrooms, then pour in half of the stock and stir well. Cook over a medium heat for 20-25 minutes, stirring often. Gradually add the remaining stock a little at a time until the rice has absorbed all the liquid. Be patient here!
Taste to check that the rice is tender; it should have a nice creamy texture. If it needs cooking for a bit longer, add a little more hot water.
Add the frozen peas and 15g of Parmesan, stirring gently to mix in. Cook for 2 minutes. Taste and season with salt and pepper if needed.
Garnish with remaining Parmesan and serve.
BEST SERVED WITH AN ICE COLD COCA-COLA ZERO SUGAR!