In a large saucepan, add the chicken broth, kosher salt, black pepper, onion powder, garlic powder, and thyme. Whisk to combine.
Add the broccoli. Bring to a boil over high heat. This should take about 5 minutes if using fresh broccoli and 10 minutes if using frozen.
Reduce the heat to medium, cover, and cook until the broccoli is very tender, 10-15 minutes.
Turn the heat off. In batches in a blender (carefully!), or using an immersion blender, blend the soup until smooth.*
Return the soup to the stockpot (if you didn't use an immersion blender). Turn the heat up to medium-low. Stir in the heavy cream and the Parmesan, then taste to see if you'd like to add more salt. Cook just until heated through, about 2 minutes. Serve immediately.
Video
Notes
How much salt you should use in this recipe depends on how salty your chicken broth is. So it's a good idea to taste the soup after you mix in the heavy cream and parmesan to make sure it's salty enough to your taste.*There are two ways to puree a soup. For a very creamy texture, working in at least two batches, carefully transfer the hot soup to your stand blender. Blend each batch until completely smooth and transfer it to a bowl. When all batches are done, return the pureed soup to the pot and proceed with the recipe. You can see the results of this method in the photos on this page - very smooth and creamy.The second method is to use an immersion blender and blend the soup right inside the pot. I used this method when filming the video, and as you can see, the soup is not as creamy. However, it's just as tasty, and using an immersion blender is easier.Which of these methods you choose is up to you. Both work and both yield great results, just different textures.When using a stand blender, never fill your blender past the maximum fill line. It's best to fill it no more than half full. If the lid of your blender wasn't designed to allow steam to escape, you’ll need to remove the center piece and drape a clean towel on top of the lid. You can hold down the lid when blending to prevent it from being pushed off, but do so without actually placing your hand - or your face - over the hot steam.