Season the mahi-mahi fillets with salt on both sides.
Leave for 5 minutes.
Put the fish into a sous vide bag together with olive oil and cook for 20-30 minutes at 135°F.
Meanwhile, sautee black beans and onions in a pan.
Pour in white wine and squid ink.
Simmer until fully reduced.
Puree the black bean mixture in a food processor.
Serve fish on top of bean puree.
Garnish with basil oil.
For the Basil Oil
Blanch the basil leaves in boiling water.
Transfer the leaves to an ice bath.
Squeeze out any excess water from the leaves.
Puree in a food processor together with the olive oil.
Notes
Leave the salt to melt and work its way into the fish's flesh. Putting it into the sous vide bag too early would leave pockmarks all over the surface of the Mahi-Mahi's flesh and that won't be too pretty at all.
Put some olive oil in the bag together with the fish to keep the exposed surfaces smooth.
Keyword black beans, mahi-mahi, sous vide, squid ink