This is a wonderful, inexpensive and very versatile dish. You can easily make it vegetarian or make it traditionally with ham. I usually don't measure my ingredients but here is a rough estimation. You can adjust accordinly. You can also make it on the stove or crockpot. I prefer crockpot as it's hands off. Just throw everything in and you have rich soup at the end of the day.
Split Pea Soup
1 lb dried split peas
1 cup each of chopped celery, carrots and onions
6-8 cups water or broth
1 cup minced ham
Salt and pepper to taste
Rinse peas well. You may soak overnight but it is not necessary. Combine everything in a large pot or a large crockpot. Let simmer 2 hours on stove or 8+ hours in the crockpot on low (4-5 on high). Make sure it doesn't get dried out. If you want a creamy texture, blend with hand blender or beaters.