Steamed Mussels with Goat Butter Recipe

Ingredients

• 3 tablespoons extra-virgin olive oil
• 2 medium white or yellow onions, slivered lengthwise
• Fine sea salt and freshly ground black pepper
• 4 garlic cloves, thinly sliced
• 1 1/2 cups medium-dry white wine, such as Viognier or Riesling
• 2 1/2 cups best-quality fish stock
• 1 cup tomato juice
• 1 sprig fresh thyme
• Pinch of saffron
• 3 pounds small black mussels, scrubbed and debearded
• 1/2 cup (4 ounces) cold goat's milk butter, cut into 8 chunks
• Handful of fresh flat-leaf parsley leaves, coarsely chopped
• Hunks of crusty bread, for serving