You could always start eating copious amounts of natural peanut butter and/or tons of nuts. Also, dried fruits are very high in calorie content (and sugar..) per serving.
The nuts pack a huge calorie punch for a tiny bit, so you could potentially consume a lot of excess calories in a healthy-ish way without having to gorge constantly.
I love granolas of all sorts but I avoid them due to the typically high calorie content.
Despite my input - I am in NO WAY a nutritionist so my suggestions may be off base.