I need high calorie, tummy friendly recipes for sick toddler that lost a lot of weight. ?

So my 1 1/2 year old son has had a terrible tummy bug for close to a week now. He was already a little guy (19 pounds) and he's lost a good 2-3 pounds with this terrible illness. He's eating today (BRAT diet) so after a few days I plan to slowly introduce other tummy-friendly foods to him. I'm trying to think of some high-calorie healthy meals that are gentle on his tummy to help him get that weight back on. I was told absolutely no dairy so smoothies are out of the question for now.