Preheat a large frying pan over medium high heat and add in the olive oil. Add the beef and season with salt and pepper. Cook to brown on all sides, stirring occasionally, about 5 minutes. Remove from heat.

Add the mushrooms to the same pan and cook to brown on all sides, stirring occasionally, about 5 minutes. Deglaze the pan with the vinegar.

Add the beef back to the pan along with the stock. Cook 2 minutes and remove from heat.

Stir in the sour cream. Stir until well combined.

Serve over the cauliflower rice and top with the parsley.

In a large skillet, heat the olive oil over medium heat until it shimmers. Add onion, garlic, and celery. Sauté until soft, about 5 minutes.

Place the cauliflower in a food processor with the S blade and pulse until the cauliflower has the consistency of rice, being careful not to overprocess.

Remove cauliflower to the skillet and cover. Cook over medium heat until soft, about 10 minutes. Season to taste with Sea Salt and Black Pepper.