Trim the broccoli, separating the florets from the thicker stems, and chopping all into bite-sized pieces.

Bring 8 cups of water to a boil in a medium pot. Add all the broccoli stems and simmer 2 minutes. Add 1/4 of the florets and simmer another 1 minute. Strain, reserving the liquid.

Put the pot back on medium heat. Add the butter and shallot. Fry for 1 minute to soften the shallot. Pour the broccoli water back into the pot. Add the chicken stock paste, a pinch of salt, and a few grinds of freshly cracked black pepper, and bring to a simmer.

Return the parboiled broccoli to the pot and add the thyme leaves. Simmer for 10 minutes, then blitz with an immersion blender until smooth (for safety, you might want to let the soup cool a bit before doing this). Turn the heat up to medium-high and simmer for 15 to 20 minutes, until reduced and thickened slightly.

While waiting on the soup, put a medium pan on high heat. I suggest using cast iron or carbon steel for this step. Add a splash of veg oil, then the remaining broccoli florets and a good pinch of salt. Let sear, stirring occasionally, until the broccoli's singed and softened (but not mushy). Remove the florets and set them aside.

Take the pot off the heat and stir in the cream. Add the charred florets. Check the seasoning and add more salt and pepper as needed. Serve hot.