We've been seeing them since several years, the first one which really caught my eye was Chris Benchetler's in 2010 (1min50).
Is buttering becoming a trend, like flat spins were not so long time ago, or is buttering really a movement that lets further room to innovation ? I'd love to discuss this on NS.
Harlaut actually took the level two steps higher by stomping a triple... but I think there's still a lot to in doubles and even "singles".