Preheat the oven to 375 F.
Grease the baking pan with some cooking spray.
Cut the bell peppers, onion and tomatoes into big chunks.
Add these ingredients to the baking tray. Add whole garlic cloves too.
Sprinkle oil all over the ingredients and then add basil powder & salt.
Place this tray in the oven and roast for 20 mins. Flip the veggies midway for even cooking.
After 20 mins, remove the tray from the oven and let it cool.
Once it's slightly cool, blend until smooth.
Add this paste to a pan and simmer on low flame.
Add 1 cup water to this soup and mix everything well.
Adjust the spices mentioned along with cumin powder and let it simmer.
Turn off the flame and then serve.
Garnish with gremolata.