Peel and chop the onion and garlic and cut the peppers into pieces. In few minutes, fry everything in the oil until translucent in a 15 inch paella skillet pan or low saucepan.
Add the rice, bay leaf and paella seasoning and fry for a few minutes more. Deglaze with a dash of sherry, bring to the boil and add the stock, if necessary some salt, diced tomatoes and peas.
Bring to the boil, reduce heat and simmer, uncovered and without stirring, for about 20 minutes until the rice has absorbed the liquid.
Bake the marinated pieces according to the instructions on the package and spoon them onto the paella. Garnish with lemon wedges and coarsely chopped flat-leaf parsley.