Peel and roughly chop the ginger (about a 1” piece). Place all ingredients in a blender and blend until smooth. This step is important in order to get the ginger pulp and juices to infuse into the marinade. In a zip-lock bag (or bowl that you can cover), add the halibut fillets and marinade. Allow the fish to marinate for at least 20 minutes but several hours is preferred if you’re able to do this step ahead of time.
Set your oven to broil, allow it to warm up then place the fish in a casserole dish with all of the marinade. Place the casserole dish on one of the top racks and allow to bake about 10 – 12 minutes, until there is a nice brown glaze on top and fish is cooked all the way through.
To Make the Ginger Peach Relish:
Combine all ingredients for the relish in a bowl, stir and refrigerate until ready to use. Allowing the relish to sit for a few hours before consuming it is a great idea because it allows all the flavors to combine.