1. Rinse, sort (discarding imperfect peas) and put peas into a large saucepan.
2. Pour 2 1/2 qts. cold water over the peas.
3. Cover and set peas aside to soak overnight.
4. The next day, set out shoulder roll.
5. Put the shoulder roll, water and onion into a large sauce pot.
6. Simmer 1 1/2 to 2 hrs., or until meat is tender.
7. Remove meat and set aside. Skim off fat from liquid, leaving about 2 tablespoons. Drain the peas and add to the broth with salt, whole thyme, and sugar.
8. Simmer 1 1/2 to 2 hrs., or until peas are tender. If necessary, skim off shells of peas as they come to the surface.