NeverSayWhen:
Supplementing with heavy cream was how I was able to reach my current weight, that and peanut butter. Sneaking a little bit into your cooking can go a long way. I added it to my rice, eggs, soups and coffee. I try to do weighted squats every other day in combination with lots of calories, and the gains in my thighs and ass have been really noticeable. And quick, too! I was surprised how fast I was busting out of my old shorts.
Be careful though. Sometimes too much heavy cream will give me a bad stomach ache. I mix it with whole milk so it's a little gentler for digestion.
Try taking Lactase, before the cream. Available at your local Wallyworld (Walmart)