Thai-Scented Asparagus Soup

INGREDIENTS

• 1/2 teaspoon black pepper
• 3 tablespoons finely chopped ginger
• 3 tablespoons finely minced lemongrass
• 3 tablespoons unsalted butter or canola oil
• 3 pounds asparagus (after trimming an inch off the stalk)
• 1 large onion, chopped
• 1 1/2 cup coconut milk
• 1/2 teaspoon fresh lemon juice
• 4 to 5 cups chicken or vegetable broth