RINSE and sort peas, discarding any objects. Pour peas into a large bowl, 4 cups of water, and cover. Let soak for 8 hours or overnight.
DRAIN and rinse peas, then pour into a large, heavy-bottom pot. Add 8 cups of water and season with salt and pepper.
BRING to a boil, then reduce to a simmer. Cook for 45 minutes or until tender.
USE a ladle to remove scum which is a white cloudy substance that forms on top of the water.
WHILE the peas are cooking. Sauce the onions in olive oil until translucent.
ADD the mushrooms and cook for 3-5 minutes. Then remove from heat and set aside. (I like to cook the mushrooms separately to maintain the meaty texture from the mushrooms.)
WHEN the peas are done, add the onions & mushroom mixture to the peas. Next, add the spices and garlic, then stir.
USE a small bowl to add miso paste and 2 tablespoons of liquid from the peas. Stir until smooth. Then add miso paste to the pot and stir. Cook for 1 minute.
USE the back of a large spoon to smash the peas. This will thicken the peas. Taste and adjust seasoning with salt and pepper.