How to Make It
Warm oil in a large pot over medium heat. Add onion; cook, stirring occasionally, until softened, 6 to 8 minutes. Squeeze spinach to extract any excess moisture. Raise heat to medium-high and stir spinach into pot, sprinkle flour over the top and mix well. Pour in milk and broth. Cook, stirring constantly (so mixture doesn't boil), until slightly thickened, about 8 minutes. Season with salt and pepper. Remove from heat and let cool slightly.
Working in batches, puree spinach mixture in a blender until smooth. Transfer all but 2 cups of soup to a large bowl. Add avocado to blender and puree until smooth. Stir into soup.
Cover and refrigerate until thoroughly chilled, at least 2 hours. Just before serving, stir in Tabasco and lemon juice. Season with additional salt and pepper, if desired. Serve chilled, garnished with lemon wedges, if desired.
MyRecipes is working with Let's Move!, the Partnership for a Healthier America, and USDA's MyPlate to give anyone looking for healthier options access to a trove of recipes that will help them create healthy, tasty plates. For more information about creating a healthy plate, visit www.choosemyplate.gov.