Heat the butter in a large saucepan and when it is bubbling, add the onion and cook over a medium heat for 5 minutes.
Add the rice and stir it around so it is well coated in the butter. Fry for 2 minutes. Pour in the wine or vermouth and stir until it has all evaporated.
Add the peas then pour in the stock and season with salt and black pepper. Give it all a gentle stir.
Bring the pan to simmer then cover with a tight fitting lid and turn the heat down low. Cook for 15 - 20 minutes until the rice is softened, stirring occasionally.
Cut the smoked salmon into strips. Alternatively, add a little oil to a frying pan and pan fry the salmon fillets over a medium heat for 2 - 3 minutes each side then set to one side. To poach the salmon, cook for 8 - 10 minutes until the salmon is cooked through. You can remove the skin from the salmon and stir it into the risotto at the end or serve as a whole fillet placed on the top.
When the rice is cooked, stir in the lemon juice, half the zest and the parmesan. Let it rest for 2 - 5 minutes to allow it to go creamy.
Serve the risotto with the smoked salmon or salmon fillet on top and sprinkle with rocket leaves
You can use pan fried salmon fillets or fresh smoked salmon. A smoked salmon risotto is slightly easier as the salmon doesn't need to be cooked. Just cut it into strips and serve over the top of the risotto. Pan fry the salmon or poach it in water for 8 - 10 minutes. Flake the poached salmon into the risotto once the risotto is cooked.As well as peas, you could use broccoli, asparagus in season, fresh spinach, sugar snap peas, mangetout or green beans. Blanch the broccoli, asparagus and sugar snap peas for a few minutes in boiling water before adding them.
Risotto is best eaten fresh but can be kept in the fridge in an airtight container for 2 -3 days. Loosen it with a little stock when reheating and make sure it is piping hot.