Meanwhile, microwave the peas according to the instructions on the back of the pack and then add them to the onions.
Once the peas and onions are cooked, use a stick blender to mix them together in the pan.
Dice the onion and sweat in a pan with oil.
Chop the mushrooms and add them into the pan with the remaining ingredients.
Simmer for 5 minutes and add seasoning to taste.