Chilled Cucumber-Avocado Soup

Ingredients

• 1 English cucumber (peeled and chopped)
• 2–3 ripe but firm avocados (peeled, pitted and chopped) about 1½ lbs
• 2 sliced scallions (white and light green parts only)
• 1 cup chicken broth (may substitute vegetable broth, more milk, or water)
• 1 cup milk
• 2 tablespoons freshly squeezed lemon juice
• ½ teaspoon white pepper (or to taste)
• ¼ teaspoon kosher salt (or to taste)
• ¼ teaspoon cayenne pepper (or to taste)
• parsley sprigs (as garnish)