I've seen mashed and riced cauliflower in the frozen food section of the supermarket where I shop. I love cauliflower, but I haven't felt inclined to try it mashed or riced; I've had no idea what to do with it. Simply as a vegetable/side dish, I'd just as soon have it un-mashed or un-riced, but these are interesting suggestions.
You can use it the way you'd use mashed potatoes or rice, except with cauliflower you're getting a vegetable at the same time. And far fewer carbs, which I try to avoid.
For the fried cauliflower rice with vegetables, I used frozen riced cauliflower with vegetables already mixed in and packaged with that purpose in mind. I fried it in peanut and sesame oil, added shredded chicken and a sauce made from the following: soy sauce, rice vinegar, garlic and maybe a touch of that ginger that comes in a tube, sriracha. I was initially going to add chopped onion and bell pepper but got lazy, decided it didn't need it and, in fact, it didn't.
The mashed cauliflower could go with something like meatloaf or pot roast or chicken or spaghetti sauce or ... well, pretty much anything, I guess.
My son really likes both, and although he likes to eat fairly healthy he also spends about 12 hours a week at the gym so doesn't have to worry about carbs or calories. He's also fairly picky and a bit snobbish about convenience foods. So for him to pronounce them "bomb" is saying something.