Melt butter in a saucepan over low heat; add onion and celery. Sauté for about 5 minutes. Add flour and mix until well blended. Stir in chicken broth and allow it to simmer for about 15 minutes. Remove from heat, strain broth. Stir the peanut butter, salt and lemon juice into the broth until well mixed. Serve hot in cups. Garnish each cup with a teaspoon of chopped peanuts. Makes 6 servings.