>I do have some fresh hazelnuts that I roasted the other day. I am
>thinking about making a sugar coating and grinding it a bit rough and
>using that as a filling. I'm doing all the experimenting I can afford
>to do

Praline paste made crudely is gritty not the same as the commercialy
made product which is smoother.
I had the same difficulty ( previously )with grinding the stuff with
the Stephan vertical cutter mixer( an institutional type of food
processor) that can accomodate 10 kg batch.weight
I had to colllect all my rough pralines from different trials and put
it into the Macintyre refiner conche and run it for a few hours and
presto! It comes out smoother( about 30 microns average as determined
by the micrometer and 20-to 50 microns particles spread with the
Hackmann gauge).
Roy