L.F.
Since she can tolerate some processed soy, you might want to try chocolate soynut butter. It is made by a brand called I.M. Healthy and is available at my local Whole Foods. It's not as good as Nutella, but it's still pretty yummy.
One of the biggest staples in my house are Yummy Brand chicken nuggets. They are available at Costco. They are dairy-free and soy-free.
Will she eat avocados? That might be another high calorie food that you can spread on a sandwich for her. Good luck. Two of my kids have allergies too, and it's a lot of work keeping them fed.