Place potatoes in a heavy saucepan. Add enough water to cover. Heat water to a gentle boil and cook potatoes until tender, about 30 minutes. Drain potates. Using a potato ricer, push potatoes through ricer into a large bowl. Add butter, ½ of the thyme and salt and pepper to taste. Mix potatoes using a spatula. Heat the cream in a microwave and add to the potatoes, mixing to a creamy texture. Set aside. Potatoes may be kept warm in a double boiler over warm water.

Heat oven to 400°. Cut tops off garlic, drizzle with olive oil and sprinkle with salt and pepper. Wrap in foil and place in oven. Roast until garlic is golden and carmelized, about 45 minutes. Remove from oven and let cool.

Heat chicken stock in a saucepan over medium heat. Add thyme sprigs, bay leaves, salt and pepper to taste. Squeeze garlic cloves into saucepan. Keep broth warm over medium-low heat, about 45 minutes. Strain broth through a fine sieve lined with cheesecloth and return to pan. Keep warm over low heat. Heat to boiling just before service.

Heat oil in a heavy stockpot to 375°. Using a mandoline or vegetable slicer, thinly slice onion into rings. Place onion rings into a large bowl and cover with milk. In another bowl, mix together flour, salt, black pepper, cayenne and ½ tsp. paprika.

Drain onions from milk. Dredge onion rings in flour and shake off excess. Deep-fry onions until golden and crisp, about 2 minutes. Drain onion rings on paper towels. Sprinkle with remaining ½ tsp. paprika.

Place cedar plank in sink and cover with water to soak, about 30 minutes. Heat oven to 425°. Drain cedar plank and place in oven. Note: the plank will begin to crack and smoke. This is normal.

Season halibut filets with Old Bay, mustard, salt and pepper. Place halibut filets directly onto cedar plank and roast in oven until done, about 15 minutes. Remove from oven and remove halibut from plank.

In a bowl or deep plate, add mashed potatoes. Top with halibut filet to side. Add hot garlic broth. Top halibut with frizzled onions. Sprinkle with thyme.