This silky tomato soup will leave everyone wanting seconds. Packed with lots of veggies, it's healthy but feels indulgent. Smarts: It's so easy to eat a ton of nutrition-packed spinach when it's cooked down in a soup.
Heat a Dutch oven over medium-high heat. Add first part of cooking oil and then garlic, onions, and carrots to heated oil with a sprinkle of salt, first part of red pepper flakes, and basil. Saute for ~5 minutes.
Add tomatoes, broth, and some salt and pepper. Bring to a boil and then simmer for 4 to 6 minutes.
Puree with an immersion blender or in batches in a blender. If using an immersion blender, you might want to transfer pot into sink since there might be spattering.
Return pot to medium-high heat and fold in mushrooms. Cook until tender, 3 to 4 minutes.
While soup finishes cooking, heat a skillet over medium-high heat. Add second part of cooking oil and then second part of red pepper flakes and shrimp to heated oil. Saute until pink on the outside and opaque on the inside, 3 to 6 minutes.
Turn off heat to soup, and stir in butter (if using) and spinach. Finish with lemon juice, and season to taste with more salt and pepper. Divide soup into bowls and top with shrimp. Enjoy your comforting soup!