Start with the sauce:
Put butter in a small saucepan over medium heat and cook until golden brown. Let cool to room temperature.

While butter is browning, whisk vinegar and egg yolks together. Slowly add browned butter to the egg yolk mixture, whisking until emulsified. Season with salt if desired. Keep at room temperature until ready to use.

Spice Rub:
Put all of the ingredients in a mortar and pestle and grind to a somewhat fine paste.

Or throw in a mini processor and pulse a few times!

Fish:
Preheat oven to 375 degrees. Cut paiche into desired serving sizes. Rub spice mixture on top of fish.

Heat a cast iron skillet with olive oil over high heat. Sear fish on unrubbed side for two minutes.

Place pan in oven for about 10 minutes or until fish reaches your desired doneness!