Step 1: In a large pot or Dutch oven, heat the olive oil over medium heat. Add the chopped onion and sauté until softened and translucent, about 5-7 minutes.
Step 2: Add the minced garlic and grated ginger to the pot. Cook for another 1-2 minutes until fragrant, being careful not to burn the garlic.
Step 3: Add the chopped celery to the pot and cook for 3-4 minutes, stirring occasionally. Pour in the vegetable broth and bring it to a simmer. Season with a pinch of salt and black pepper.
Step 4: Add the kale to the simmering broth. Cook for about 5 minutes, or until it begins to wilt. Then, add the fresh spinach, stirring gently until all the spinach has collapsed into the broth.
Step 5: Carefully transfer the soup to a high-speed blender (in batches if necessary). Alternatively, use an immersion blender directly in the pot. Blend until completely smooth and creamy. If you prefer a thinner consistency, you can add a little more vegetable broth or water.
Step 6: Return the blended soup to the pot (if using a stand blender). Stir in the freshly squeezed lemon juice. Taste and adjust seasonings as needed, adding more salt, pepper, or lemon juice to your preference. If desired, add a pinch of red pepper flakes.
Step 7: Serve hot and enjoy your revitalizing green detox soup recipe!