1. 1. Saute the Aromatics: In a large pot or Dutch oven, heat the olive oil over medium heat. Add the chopped onion and cook until softened and translucent, about 5-7 minutes. Stir in the minced garlic and cook for another minute until fragrant, being careful not to burn it. The onions should be soft and slightly golden, indicating they’ve released their sweetness.

2. 2. Add Broccoli and Broth: Add the fresh broccoli florets to the pot. Pour in the vegetable broth. Bring the mixture to a boil, then reduce the heat to a simmer, cover, and cook for 10-12 minutes, or until the broccoli is very tender. You should be able to easily pierce the broccoli stems with a fork.

3. 3. Blend Until Smooth: Carefully transfer the soup mixture to a blender. Alternatively, use an immersion blender directly in the pot. Blend until the soup is completely smooth and creamy. Be cautious when blending hot liquids; work in batches if using a traditional blender and ensure the lid is vented. The soup should have a uniform, vibrant green color.

4. 4. Return to Pot and Add Dairy: Pour the blended soup back into the pot over low heat. Stir in the milk and heavy cream (if using). Heat gently, stirring frequently, until the soup is warmed through. Do not boil at this stage, as it can cause the dairy to curdle.

5. 5. Melt in the Cheese: Remove the pot from the heat. Gradually stir in the shredded cheddar cheese, a handful at a time, until it is completely melted and incorporated into the soup. Stir continuously to ensure the cheese melts smoothly without clumping. The soup should become even creamier and slightly thicker.

6. 6. Finish with Lemon and Season: Stir in the fresh lemon juice. Season the soup with salt and black pepper to taste. If desired, add a pinch of red pepper flakes for a subtle kick. Taste and adjust seasonings as needed, ensuring the lemon flavor is bright but not overpowering.

7. 7. Serve Warm: Ladle the creamy broccoli lemon soup into bowls and serve immediately.