Boil 4 cups of water. Dissolve the baking soda in the water. Put the peas in a bowl, and pour the boiling water over them, ensuring at least 3 inches of water above the peas. Leave the peas to soak for 12 hours.

Drain and rinse the peas. Place in a medium-sized pot and add three cups of water. Bring to a boil, cover, reduce the heat to medium-low, and simmer for about 30 minutes, stirring occasionally, or until the desired consistency is reached. Once the peas have fully broken down add salt.

If the peas are too watery, continue to simmer with the lid off until it thickens to your liking. If the peas are too thick, add a little water. Taste again and add more salt if needed.

Once the peas are done they will start to thicken the longer they sit. If reheating them later or the next day, add a little more water.