Bring a large pot of salted water to boil on the stove over high heat.
Add the cauliflower and boil for 15 minutes, or until the cauliflower is fork tender.
Drain the cauliflower, then place it back in the pot.
Use a potato masher to mash the cauliflower.
Add the butter, heavy cream, salt and black pepper to the pot.
For a more textured mashed cauliflower, mash the ingredients together with the potato masher. To make them extra smooth and creamy, transfer the ingredients to a blender or food processor and puree until smooth.
Use a spoon to stir in the cheese and chives.
Reheating: Mashed cauliflower can be reheated in the microwave for 2 minutes. If it becomes too thick, add 1 tablespoon of liquid, either milk, cream, broth or water.
Freezing: this mashed cauliflower can be frozen for up to 3 months. I recommend reheating frozen mashed cauliflower in a pot on the stove over medium heat and adding more liquid as needed.