You can adapt this recipe as far as you like, in terms of amounts used, so long as you use 110g sugar to each egg white. In a TM31, I wouldn't be inclined to go beyond 6 egg whites however. I have successfully made this with just one egg white too.
Ingredients
3 Egg-Whites, room temperature
330g White sugar (brown if you don't mind them not being white)
Pinch of Salt
Instructions
Put the sugar in the mixing bowl and pulse for 10 seconds on Turbo.
Place the butterfly in the bowl and add the egg whites along with a pinch of salt.
'Cook' at 37C for 7 minutes on speed 2, no MC.
Leave the mix to cool for 10 minutes with the lid off.
Mix again for 7 min/speed 2.
Either pipe the mixture with a piping bag into small circles, or a large 'pie' for pavlova-style deserts, or dollop the mix onto a baking tray in spoonfuls, leaving space for expansion.
Cook for about 60-90 minutes on 100C° to 120 min at 80C° depending on your oven and meringue sizes - as well as how chewy you want it.
When finished, leave in the oven to dry out while cooling down.
Recipe by Keeper of the Kitchen at https://www.keeperofthekitchen.com/2013/10/28/easy-thermomix-meringues/