Does anyone have a good Mooshroom grinder design?

[Runekaster]

For all my other spawners, I'm using flowing water to take the mobs to a lava blade. But since Mooshrooms only spawn on mycelium, the water prevents them from spawning at all. I've tried using mycelium below the water, above the spawner, and for the walls of the spawning cube, but nothing is working. Does anyone have a working design I could copy?