West African Chicken Stew

Name: West African Chicken Stew
Ingredients: 1 tablespoon vegetable oil; 3 pounds boneless chicken, cut into 1/2 inch cubes; 1 large onion, chopped; 5 medium potatoes, peeled and cubed; 2 cloves garlic, crushed; 1 teaspoon coarse ground black pepper; 1 teaspoon salt; 1 teaspoon ground coriander; 1 teaspoon ground cumin; 1 teaspoon crushed red pepper flakes; 1 cup water; 1 cup chicken broth; 3/4 cup peanut butter; 2 cups chopped fresh spinach