In a large soup pot over medium-high heat, saute chopped onion until it start to soften and turn golden, approximately 10 minutes. Add the garlic and stir, until it becomes fragrant, approximately 1 minute. Add in package of frozen pepper strips, diced tomatoes, tomato sauce and oregano. Stir to combine and cook until peppers soften, approximately 10 minutes. Add broth and mix well. Bring to boil then reduce to simmer, 10 minutes. Use an immersion blender to puree. Adjust seasonings with salt, pepper to taste.