Yellow split peas are full of protein and other nutrients, making them a nutritious ingredient to add to soups and other savoury recipes. A soaking period is not required for yellow split peas; however, soaking them in a water and baking soda mixture will produce peas that purée into a smoother soup after cooking. After soaking and rinsing the yellow split peas, they cook quickly by simmering on the hob and will be ready to eat in only an hour or two. Two cups of dried yellow split peas will yield approximately four servings.
Place the peas into the large bowl. Cover the peas with cold water and sprinkle 1 teaspoon of baking soda over the surface of the water. Stir the peas, water and baking soda to incorporate. Allow the yellow split peas to soak for between eight and 10 hours. Do not allow them to soak longer because the flavour of the peas may change with extended soaking.
Drain the peas and rinse them several times under cold water to remove all remains of the baking soda. Place the soaked yellow split peas into the stockpot.
Cover the peas with cold water and place the stockpot onto a burner. Set the burner to medium and bring the peas and water to a simmer. Reduce the heat slightly and simmer the peas for approximately one hour. Cover the stockpot and stir occasionally while simmering.
Check the peas while they are cooking and add more water if the water boils down too much. Keep the water amount just over the peas.
Purée the peas when they are thick and tender. Remove the stockpot from the hob and use the immersion blender to purée the peas in the stockpot.
Chop the onion and celery into small pieces and add to the stockpot. Add salt and pepper to taste. Cook the vegetables and seasonings with the puréed yellow split peas. Simmer just long enough to cook the vegetables and blend the flavours.
Remove from the heat and serve immediately.
Cook yellow split peas first alone without adding any other ingredients because this will produce a smoother purée.