Preheat your oven to 400°F. Place the red bell peppers and whole garlic cloves in a bowl.

Drizzle with olive oil and season with salt and pepper. Spread them out on a baking sheet and roast for about 40 minutes, until the peppers are soft and slightly charred.

While the peppers are roasting, heat a little olive oil in a large pot over medium heat. Add the chopped yellow onion and cook until soft and translucent, about 5 minutes.

Add the roasted peppers, garlic, and sun-dried tomatoes to the pot with the sautéed onion. Pour in the vegetable broth and allow the soup to simmer for 10 minutes.

Remove from heat and carefully blend with an immersion blender until smooth. Stir in the lemon juice and adjust salt and pepper to taste. Serve with Greek yogurt or sour cream drizzled on top. Garnish with basil and serve hot.