Cook bacon in a Dutch oven over medium heat until crisp; remove bacon, reserving drippings in pan. Crumble bacon.
Saute onion in reserved drippings in Dutch oven 7 to 8 minutes or until tender. Add field peas and 2 1/2 cups water; bring to a boil. Reduce heat, and simmer 30 minutes or until peas are tender; stir in salt and pepper. Stir in spinach; cook over medium heat 3 to 5 minutes or until spinach wilts. Drain. Sprinkle each serving with bacon.
Prep: 15 min, Cook: 45 min.
*1 (16-ounce) package frozen field peas may be substituted for 3 cups fresh peas.