Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Peel and dice the parsnips and carrots into half-inch cubes to ensure even cooking.
In a medium bowl, toss the diced root vegetables with olive oil, sea salt, and black pepper until well coated.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 20-25 minutes until tender and slightly caramelized.
While the vegetables roast, whisk together the Greek yogurt, lemon juice, chopped fresh dill, and garlic powder in a small bowl to create the sauce.
Gently flake the smoked trout into large, bite-sized pieces, removing any skin or small bones if necessary.
Once the vegetables are finished, divide them between plates and top with the flaked smoked trout.
Drizzle the lemon-dill yogurt sauce over the trout and vegetables before serving warm.