Creamy Vegan Sweet Potato and Corn Chowder

Name: Creamy Vegan Sweet Potato and Corn Chowder
Ingredients: 3 small sweet potatoes, peeled; 1 Yukon Gold potato, peeled; 2 tablespoons olive oil; 1 cup chopped celery; 1/2 cup chopped sweet onion; 2 cloves garlic, minced; 2 cups corn kernels; 1 teaspoon chopped fresh ginger (optional); 2 cups soy milk; 1 cup vegetable broth; 1 tablespoon chopped fresh parsley; 1 teaspoon dried rosemary (optional); 1 teaspoon sea salt; 1 teaspoon ground black pepper; 1 bay leaf; 1 pinch cayenne pepper (optional); 1/4 cup all-purpose flour