Set a large 6 to 8-quart sauce pot over medium heat. Add the olive oil, diced onion, fennel, and garlic. Add in 1 teaspoon of salt and ½ teaspoon of cracked black pepper. Stir and sauté for 5 minutes to soften, then stir in the diced bell peppers, and carrots. Stir and sauté another 3 to 5 minutes.
Pour in the dried lentils, 1/3 cup lemon juice, all lemon zest, grated ginger, turmeric, and vegetable broth. Bring to a boil. Stir and simmer for 30 minutes, partially covered.
Remove the lid and stir in the corn and spinach. Simmer another 3 to 5 minutes. Taste, then salt and pepper as needed.
Notes
The soup will keep well in the fridge for up to 5 days. However, I do recommend waiting to add the spinach until you reheat it and are ready to eat.To Freeze: Transfer to freezer-safe containers with a lid. Wrap in a layer of aluminum foil for extra freezer burn protection. Freeze for up to 3 months.Thaw in the fridge overnight, and reheat in the microwave or on the stovetop.