I initially started to make walnut butter and I ended up showing you the homemade nutella recipe - which, in fact, is still walnut butter to which you add cocoa powder and some more sweetener, according to your likes. It has a stronger walnut taste than the bought nutella does and, of course, the texture a bit more rough (it also depends on the type of blender). But it's very good - vegetarian, healthier and suitable for the low carb diet (if you use low glycemic sweeteners).
In the pictures you can see my version with powdered sweetener but, no matter how fine it is, you can still feel it in the texture. I would say it would better to use liquid sweetener like honey or your favourite syrup (agave or maple syrup). As for the walnuts, the ideal is to use hazelnuts, but I've also made this recipe with Romanian walnuts. It's got a stronger flavour and a more specific, slightly bitter, taste, but it's still very good - so, if you want to try it, you can use any nuts you have.
Also, you will notice in the steps of the recipe that I used 2 different food processors to make this homemade nutella. This is only because I wanted to spare the blender from the extra effort, as making walnut butter is hard work for any blender. Mine has a fuse that makes it stop when it's overheated, so I had to wait for 2-3 hours. Be careful not to break your blenders and use the food processors which are more powerful and more resistant.