I made my first split pea soup today because someone gave me 4 pounds of split peas. The ratio was 1 lb. of dried split peas to 2 1/2 quarts total of rich chicken broth and water. It tastes wonderful. After I used an immersion blender, I found that it was not as thick as the split pea soups I have had, and it split after cooling. Anything I can do to make it thicker and not split?