Combine miso, sugar, liquid aminos, and sake in a bowl. Mix well and emulsify.
Divide salmon filet into 4 even pieces, or have your 4 pieces ready.
Fully coat each piece in the marinade and place onto a Pyrex tray leaving space in between each piece. Cover with plastic wrap and refrigerate for 24-48 hours.
After marinating time has passed, preheat your Fontana oven to 500 in preparation for fish.
Remove salmon from the refrigerator and remove some of the marinade making sure to leave a little bit on top to bake. Transfer fish onto a baking pan and place into the oven.
Bake for 3 minutes and then turn up the heat to 600. Cook until the salmon is cooked through and reaches an internal temperature of 135 Fahrenheit. Remove from the oven and serve immediately.
