I've been making this base for the last few hours (also pre-cooking 2.5lb of chicken) I do agree with another comment about not being impressed/sure whilst in the process, I've found it up and down, first thought not enough onion 600g was 1.75 super large onions, then I started too like the smells after adding the spices and 1st half of spice mix.
When cooling quite allot of oil to the surface, nice, then blended, it looks like Carrot soup and had in the back of my mind adding another kettle full of water is going to be really runny. Anyway added the Ajowan, extra water, puree, rest of spice mix, coriander and was doubting if I will see oil again, been simmering an hour (approx.) and the oil is coming up nicely all around the edges, nice and dark color. Taste at the moment to me is a bit like a slightly spicy Carrot & Coriander soup, smell is good, the oil around the edges tastes great, but I'll wait and see as every time I doubt this base so far it's come back to surprise me.