Preheat oven to 400°F (200°C).

Cut red bell peppers in half, remove seeds, and place skin-side up on a baking sheet. Roast for 30-40 minutes, or until skin is blackened and blistered.

While peppers are roasting, heat 1 tablespoon of olive oil in a Dutch oven over medium heat. Add onion and garlic and sauté until softened, about 5 minutes.

Add potatoes and vegetable broth to the Dutch oven. Bring to a boil, then reduce heat and simmer for 20 minutes, or until potatoes are tender.

Once peppers are cool enough to handle, peel off the skin and remove the stems. Add the roasted peppers to the Dutch oven.

Using an immersion blender, puree the soup until smooth. Season with salt, pepper, and any other desired spices.