Preheat oven to 425ºF. Line a rimmed baking sheet with foil and grease it with a bit of avocado oil to prevent the fish from sticking. Set aside.

Heat a large pan over medium-high heat and when hot, add a teaspoon of avocado oil. Add the mushrooms and cook until they begin to soften, about 5 minutes. Add the broccoli and continue to cook, stirring occasionally until just beginning to soften, another 5-8 minutes. Add the garlic and cook until fragrant, about one minute more. Drizzle on a teaspoon or two of Unagi Sauce and add a tablespoon of water. Cook until no liquid remains and the broccoli is tender-crisp.

While vegetables are cooking, lay fish filets onto the prepared baking sheet and bake for 10-12 minutes, or until the fish just flakes when tested with a fork.

Divide the vegetables between two plates. Top with fish and drizzle with remaining Unagi Sauce.