Preheat the oven to 356°F (180°C).

Peel the potatoes and cut them into big cubes. Cut the small peppers in half and remove the seeds. Leave the cherry tomatoes whole. Dice the onion.

Place the potatoes, peppers, cherry tomatoes, and diced onion on a baking tray. Drizzle with olive oil, sprinkle with salt and black pepper, and toss them to coat evenly.

Roast the vegetables in the preheated oven for about 30 minutes or until they become soft and slightly caramelized.

Transfer the roasted vegetables into a large pot and add enough water or vegetable stock to cover them.

Use a blender to puree the vegetables until you achieve a smooth and creamy texture. If needed, you can blend the soup in batches.

Once you have a creamy texture, put the pot back on the stove and warm up the soup over medium heat. If the consistency is too dense, you can add extra water or vegetable stock to achieve the desired thickness.

Season the soup with salt and black pepper to taste. If you prefer a spicier flavor, you can add some dry chili flakes.

Transfer the soup into serving bowls.

Add a spoonful of Greek yogurt to each bowl, swirling it gently into the soup.

Drizzle some olive oil over the soup and garnish with fresh basil leaves and lemon peel.