Method

Cut fish into 6 equal pieces; set aside.

In coffee grinder, grind mushrooms until very fine powder; spread in shallow dish. Sprinkle salt and pepper over fish. Dip each piece in mushroom powder, turning to coat. Place on plate, cover loosely with plastic wrap and refrigerate for 4 hours. (Make-ahead: Refrigerate for up to 24 hours.)

Roasted Garlic Potatoes:
Cut 1/2 inch (1 cm) off top of each garlic head; remove any loose papery skin, leaving head unpeeled. Wrap in foil. Roast in 425°F (220°C) oven for about 40 minutes or until very soft when squeezed.

Meanwhile, in large saucepan, bring lightly salted water to boil. Peel and cut potatoes into large chunks. Cook in boiling water for 15 to 20 minutes or until tender but not mushy. Drain well in colander.

Return potatoes to saucepan; heat over low heat, shaking pan occasionally for 2 minutes to dry completely. Turn off heat. Squeeze garlic out of skins into potatoes; add butter and mash until smooth. Add cream, chives, salt and pepper; mash or stir until fluffy.

Meanwhile, in cast iron skillet or grill pan, melt butter over medium-high heat until starting to brown. Add fish, skin side down; cook for 3 minutes. Transfer to 425°F (220°C) oven and roast for 10 minutes or until fish is opaque and flakes easily when tested.

Mound potatoes on each plate; top with fish. Gently drizzle browned butter over top.