1) Preheat oven to 400 F.

2) Add cauliflower to a pot, fill with water and cover.

3) Bring to a boil over medium-high heat and cook until florets are fork tender, 8 to 10 minutes.

4) Drain well and season to taste; mash until smooth using a potato masher.

5) Melt avo oil in a skillet over medium heat.

6) Add the onion, celery, garlic, and cook 2 to 4 minutes; stirring often.

7) Add the ground beef and cook until browned, 4 to 5 minutes.

8) Add the mushrooms and continue cooking until mushrooms are soft.

9) Pour in the beef stock and season to taste, cook 4 to 5 minutes longer.

10) Place the beef mixture in a casserole dish and top with the mashed cauliflower.

11) Bake 15 to 20 minutes, or until the mashed cauliflower is nicely browned.

12) Serve with some raw greens!