I don't know that there's really a name for it beyond "combining recipes" or more generally "modifying/changing/tweaking recipes." If your goal is to get the best of both worlds, then you could perhaps say you're trying to improve or perfect your recipe for something.
In the end, you're just making additional variations of an existing dish, presumably with the goal of finding a variation you really like. It's a really good method of doing so, and you should definitely be proud if you manage to succeed at getting what you want out of it! But you started out with raita recipes and you made another raita recipe.
If you were combining different dishes, from different cuisines in particular, resulting in a dish that couldn't exactly be described by just one original name, then fusion would be a good name, as Lorel said.