Yes, split pea soup counts as a protein (in contrast to peas, which are a starchy vegetable). 6 oz. of pure split peas would be your protein serving, but with soup you need to factor in that there may be extra liquid and/or vegetables as well. If the soup is made with a lot of carrots, onions, and other vegetables, perhaps weigh out 12 oz. of soup and count it as your 6 oz. protein and 6 oz. cooked vegetable servings. If there are few or no vegetables, but the soup is very runny, perhaps weigh 10 oz. of soup and count it as your protein only.