Salmon with Sorrel Soup from Soup: A Way of Life by Barbara Kafka

Ingredients

• 1½ ounces (45 g) sorrel, stemmed and cut across into narrow strips (¾ cup)
• 1 teaspoon kosher salt
• Freshly ground black pepper, to taste
• ½ cup (125 ml) heavy cream
• 1 small onion, cut into quarters
• 2 medium cloves garlic, smashed and peeled
• One 1- pound (450- g) piece salmon fillet (about 1 inch [2.5 cm] thick), any pin bones removed with a pair of pliers
• One 18- ounce (510- g) salmon head, cut into 4 or 5 pieces