Xtreme formulations ICE BCAA. It’s kinda pricey but it comes in different flavors (it doesn’t taste like shit like regular powdered BCAA’s do) and Berardi recommends it.
I mix half ICE BCAA and half ON BCAA 5000. You still get the flavor from the ICE BCAA and can save a few bucks buy also using the less expensive ON brand.
It will all eventually dissolve just shake your container every few minutes after initially mixing.