Step 1: Heat the olive oil in a large pot over medium heat. Add the sliced leeks and sauté for 5-7 minutes until soft and translucent.
Step 2: Stir in the garlic, ginger, and turmeric. Cook for another 1-2 minutes until the spices are fragrant, being careful not to burn the garlic.
Step 3: Add the broccoli florets and celery to the pot. Stir to coat the vegetables in the aromatics and cook for 3 minutes.
Step 4: Pour in the vegetable broth. Increase the heat to bring to a boil, then reduce the heat and simmer for 15 minutes or until the broccoli is fork-tender.
Step 5: Stir in the fresh spinach and kale. Let them wilt for just 1-2 minutes to preserve their bright green color.
Step 6: Use an immersion blender to blend the soup until completely smooth. If using a standard blender, work in batches and be careful with the hot liquid.
Step 7: Stir in the lemon juice and season with salt and black pepper. Serve warm, garnished with pumpkin seeds if desired.