Tilapia with Balsamic Butter Sauce

Balsamic butter sauce 1/4 cup balsamic vinegar 1 garlic clove, minced

2 cups sugar snap peas, strings removed

2 tablespoons olive oil 6 4- to 5-ounce tilapia fillets

1/2 cup (1 stick) plus 1 tablespoon chilled unsalted butter, cut into 1/2-inch cubes

preparation For thyme mashed potatoes: Boil potatoes until tender, about 20 minutes. Drain; return to pot. Add butter, 6 tablespoons cream, and thyme; mash. Season with salt and pepper. Do ahead Can be made 2 hours ahead. Let stand at room temperature. Rewarm over medium heat, stirring often and adding more cream by tablespoonfuls if dry.

For balsamic butter sauce: Simmer vinegar and garlic in small saucepan over medium heat until reduced to thick syrup, about 5 minutes. Set aside.

Cook snap peas in boiling salted water until crisp-tender, about 1 minute. Drain. Return to same pan; set aside.

Heat 1 tablespoon oil in each of 2 large skillets over high heat. Sprinkle fish with salt and pepper. Sauté fish until golden, about 2 minutes per side.

Rewarm balsamic syrup over medium-low heat. Whisk in 1/2 cup butter 1 piece at a time. Add remaining 1 tablespoon butter to peas; stir over medium heat until warmed. Season with salt and pepper.

Divide potatoes, tilapia, and peas among plates; drizzle with sauce.