Add the 1 tablespoon cultured unsalted butter, 80 grams celery and 250 grams onion into a pot and sauté until the onions are soft and just starting to brown, but do not caramelize them completely. While fully caramelizing will produce more flavor it will make your soup brown.
Add the 1 pound peas and 3 cups ham stock. Simmer until the peas are tender. 15-20 minutes.
1 pound peas, 3 cups ham stock
Pour the soup into a blender and carefully blend. You can adjust the texture of the soup by the length of time you blend it (longer = more creamy, shorter = more chunky).
Adjust the 1 teaspoon salt to taste. My ham stock was very low sodium so I added about 1 teaspoon of salt.
1 teaspoon salt
Pour the soup into bowls and garnish with diced ham. The smaller you dice the ham, the better it will float on top of the soup. Finish with a generous amount of ground black pepper.