Remove casing from sausage and add to a frying pan on medium heat. Break up sausage and let fat melt.
Add red onions, let soften slightly.
Add mushrooms.
Once mushrooms are cooked add the red and yellow peppers. Fry for 5 minutes.
Turn off heat and add the green onions.
Let cool completely and keep in a plastic container in the fridge for up to a week.