Line a slice tin with baking paper. (average size, 27.5cm x 17.5cm x 3.5cm)
Place butter, marshmallows, chocolate, vanilla and salt into Thermomix bowl. Melt 7 min/100°C/speed 2. Cool slightly before proceeding.
Place rice bubbles into a large mixing bowl. Pour over the marshmallow mix and stir to combine.
Press into prepared tin, flatten with wet hands and then score the 16 pieces that will be each reindeer. Add eyes and the jaffa noses then place the whole thing into the fridge to set for a couple of hours.
If you need to glue the noses on, (some will stick and others may not) melt a little bit of extra chocolate in the microwave and use as glue. This is also how you can stick the antlers on. You really won't see the 'glue' when they are set and finished.