Is there a term for the blending of different recipies of the same type?
Fusion is a great word for a thorough mixing of things, conveying the idea of almost welding them together. So I see what your friend means when she describes your fusing together of different recipes for a particular dish as fusion cooking. 

But when people use the term fusion in relation to cooking they often mean the marrying together of different types of cuisine, like for example, an "Asian Fusion" style restaurant might serve dishes from a variety of different countries within Asia or dishes made with ingredients from a variety of different parts of Asia ... like maybe curry with tofu in it or, who knows, sushi with paneer? They can be as creative as they like, and it's called "Fusion".

So if your friend were to write a review of your restaurant and call it a "fusion restaurant", she might need to add a little extra explanation to avoid con-fusion.