Storecupboard: curry sauce

I like the idea of keeping portions of curry sauce in the freezer for when I fancy something flavoursome and spicy.  Diane (a blog friend) does it and finds it very useful.  I looked around for ideas and then created this, totally out of what I have in my stores.  It made quite a hot sauce so adjust the hot spices if you like.

Ingredients: to make six single portions
good knob of butter
A largish onion, peeled and chopped.
a can of coconut milk (I used half fat because that's what I had)
a knorr vegetable stock pot
a bit of water
about 20-ish mls red lentils (to help to thicken the sauce)
have some boiling water ready in the kettle

And for the paste:
1.5 tbsp curry powder (mine is mild, hence the added chilli lower down)
1 tbsp garam masala (mine is 'roasted', normal would be fine, I am sure)
1.5 tsp crushed ginger
1tsp crushed garlic
1 tsp crushed chilli (optional)
2 tbsp tomato puree
a splash of water.

Method
Make up the paste by putting all the paste ingredients in a bowl and mixing well into a paste.

Melt the butter in a largish saucepan.  Drop in the onion, mix it all well and fry gently until the onion is softening and translucent.
Add the curry paste, increase the heat and stir it all in, mixing well.  Then allow to fry for a couple of minutes, stirring all the time (smells wonderful).

Pour in the coconut milk and mix well until the paste is all incorporated.  I rinse out the can with a little water which also goes in, to get the last dregs!.  Add the stock pot and some boiling water (about half a canful, maybe a bit more.  This was the one thing I forgot to measure!

Bring to a steady simmer and add the lentils.  Cover and simmer for about half an hour, stirring occasionally.

Taste and add salt if needed.

Allow to cool a little before zizzing into a smooth sauce.  I used my Thermomix but I am sure my hand blender would have done the job.  Then push it through a fine seive if you want a completely smooth sauce.

Portion out and freeze if not using that day.
 Use with leftover meat or pulses and vegetables.  I would fry more sliced onion, add the meat and veg, add the sauce, simmer for a short time and then maybe add cream or yogurt or milk.  I would use thickening granules if necessary.