1. Place potatoes in a large saucepan, add garlic, cover with cold water, and cook over high heat 15 minutes or until potatoes are tender.

2. While the potatoes cook, place the bread in a large bowl. Spoon 2–3 tablespoons cooking liquid from potatoes over bread. Stir with a fork until smooth. Add yogurt, 2 tablespoons olive oil, and lemon zest and juice; stir until a smooth paste forms.

3. Place a large bowl in the sink, and set a colander on top. Drain potatoes and garlic, reserving cooking liquid. Transfer potatoes to bread mixture, and mash until smooth. Add reserved cooking liquid 2 tablespoons at a time until mixture takes on the consistency of loose mashed potatoes. Stir in 1/4 teaspoon salt and 2 teaspoons olive oil. Cover and keep warm.

4. Preheat grill pan over medium-high heat. Drizzle fish with 1/2 teaspoon olive oil, and sprinkle with remaining 1/4 teaspoon salt and thyme. Cook 2–3 minutes on each side or until fish flakes easily with a fork. Transfer to a plate; cover and keep warm.

5. Place bell pepper, zucchini, and red onion in a large bowl. Drizzle with remaining 1/2 teaspoon olive oil; toss to coat. Arrange bell pepper in grill pan, and cook 5 minutes over medium heat. Add zucchini and onion; cook 10 minutes or until vegetables are tender, turning as necessary for even cooking.

6. Serve halibut with grilled vegetables and skordalia.