Place water into the Thermomix bowl and the tails into the Varoma dish. Set Varoma into position.
Steam 25 min/Varoma/speed 4. Check for done-ness, they should be bright orange and smell faintly sweet. Leave in the Varoma to stay hot.
Meanwhile, grill the lettuce by heating a griddle pan to a medium high heat. Using a dash of EVOO, place the cut side of the lettuce down and cook until grill marks are evident, turn and repeat on the outside. Remove from the heat and place a few pieces of the butter on top of the lettuce while it's still hot to melt.
To serve, cut the top side of the tails with one deft crack of a good knife, open and dollop with butter. Serve on a plate with the lettuce and garnished with herbs.
We found it best to use the lettuce leaves to wrap a piece of the tail flesh, with some butter, and then pop it in your mouth. Easy flavour delivery!
You don't have to grill the lettuce. For Pemberton we ended up not doing so, just using fresh lettuce and it was delish!