Prepare the following vegetables for the gumbo:
2 medium bell peppers (red, yellow or green, or a mix), cored, seeded, and cut into 1/2-inch pieces
1 large onion, coarsely chopped
2 celery ribs, cut into 1/2-inch pieces
2 garlic cloves, minced
In a large Dutch-oven or soup pot, heat 2 tablespoons of vegetable oil until shimmering. Add the bell peppers, onion, celery, garlic and cayenne. Season the vegetables with salt and pepper and cook them over moderately high heat until they are softened, about 5 minutes.