Place cauliflower rice in a large glass bowl and cook in microwave on high for 8 minutes, mixing halfway through to ensure even cooking.
Add butter, half & half, & salt and stir to combine.
Cook for an additional 8 minutes on high, mixing halfway through to ensure even cooking, or until riced cauliflower is cooked through and softened.
Place cooked cauliflower mixture in the food processor and process for about 1 full minute, scraping down the sides to ensure all of the riced cauliflower has been whipped to a smooth consistency.
Transfer to a serving bowl, add the sour cream and freshly ground black pepper, and mix well.
Taste & adjust seasonings to your preference. Serve immediately.