Step 1

Place the dried marrowfats in a large Dutch oven and sprinkle the baking soda on top.  Pour in 8 cups of boiling water and stir, then cover and let stand at room temperature for about 12 hours.  (You can go up to 24 hours if you'd like.)

Step 2

Drain the marrowfats in a large colander, making sure to rinse them very thoroughly to remove the baking soda.  They still will have a somewhat bitter flavor from the baking soda, but this will go away once they are cooked.

Step 3

Return them to the Dutch oven and cover with filtered water (about 5 1/2 cups).  Stir in the salt and pepper, then cover.

Step 4

Set the pot over medium-high heat and bring to a simmer, then turn down the heat to low and simmer for 10-15 minutes, stirring frequently, until the peas are thick and mushy.  Skim off any foam or loosened skins, and be careful not to overcook, or they will not be as chunky.

Step 5

Leave them plain, and serve hot with a variety of toppings, such as lemon wedges, cream, butter, mint sauce, and malt vinegar.  Mushy peas also taste great alongside fish and chips or meat pies.