Marmite and Onion Roast Potato

This recipe isn't quite perfect yet, but the first try went pretty well.  I'm trying to recreate the taste of cheese and onion crisps.

I basically made my cheat's roast potatoes, only using the margarine/marmite mixture and onion salt.  There's an odd kind of beef gravy flavour on the bits where there's more marmite mixture than onion salt, but some are just perfect.