Ingredients

1/4 cup (1/2 stick) unsalted butter, room temperature

2 tablespoons (packed) minced shallot

1 tablespoon chopped fresh Italian parsley

1 tablespoon chopped fresh chives

1 tablespoon fresh lemon juice

2 garlic cloves, minced

2 teaspoons chopped fresh thyme

1 teaspoon grated lemon peel

4 5x3x1/2-inch slices crusty sourdough bread

1/4 cup extra-virgin olive oil

2 pounds mussels, scrubbed, debearded

Additional chopped fresh chives

Preparation

Mix first 8 ingredients in small bowl. Season herb butter with salt and pepper. (Can be prepared 1 day ahead. Cover and chill.)

Position 1 rack in top third and 1 rack in bottom third of oven; preheat to 500. Brush bread on both sides with oil; place on baking sheet. Place bread on top oven rack; toast until golden, turning once, about 5 minutes per side.

Meanwhile, place mussels in wide ovenproof pot. Cover, place on bottom oven rack, and roast just until mussels open, about 5 minutes. Remove pot from oven and discard any mussels that did not open. Add herb butter to mussels; stir until melted. Season to taste with ground black pepper. Divide mussels and juices from pot among 4 bowls. Sprinkle with additional chopped chives. Top each serving with sourdough toast and serve.