Spicy Peanut Soup
["1 medium red onion, chopped", "1 (13 3/4 oz.) can chicken broth", "1 3/4 c. milk", "1/8 tsp. ground red pepper", "1/8 tsp. black pepper", "1 celery stalk, sliced thinly", "1 Tbsp. vegetable oil", "1 Tbsp. all-purpose flour", "1/2 c. natural chunky peanut butter"]
["Reserve 3 tablespoons chopped onion for garnish.", "Combine broth, milk and peppers in a bowl; stir until combined."]
["red onion", "chicken broth", "milk", "ground red pepper", "black pepper", "celery stalk", "vegetable oil", "flour", "natural chunky peanut butter"]