Preparation

• Position a rack in the center of the oven, and heat the oven to 450°F.
• Finely chop 1 of the garlic cloves and mix with the butter. Spread evenly on the bread and toast until crisp and browned, about 9 minutes.
• Meanwhile, combine the basil, the remaining clove of garlic, and oil in a blender or food processor, and pulse until combined. Add the walnuts, and blend until almost smooth. Season to taste with salt. Transfer to a small serving bowl.
• Sprinkle the thyme in the bottom of a 12-inch cast-iron skillet, top with the mussels, and roast until they open, about 5 minutes. Serve the mussels with the bread and pesto on the side. The shells may be a little brittle, so remove the meat gently.