Preheat your oven to 200*C
Chop off the stems of the mushrooms carefully. Chop up the stems finely and stick 'em in a bowl with the meat and everything else and mix well.
Once mixed well, take about a tablespoon or so of meat mixture (depending on how big your mushrooms are) and cram it into each mushroom. In theory, you could top these with cheese. That would have been rather nice!
With the remaining meat, roll into meatballs and stick them on a tray. I made about 15 more meatballs.
Bake in the oven for 40 minutes.
Serve mushrooms immediately. (Served with mashed cauliflower that was cooked in the leftover thai chicken soup from yesterday... see what I did there?)
Save meatballs to snack on later. Lovely cold!