While this is delicious as it is, particularly when served with some rice to soak up the juices and a spoon to slurp it up, you can thicken the sauce a little. Make a slurry by mixing 1 part cornflour (or cornstarch if you are in the US) with 2 parts water. Don't add the cornflour/starch directly into the liquid.
Stir 1 teaspoon into the curry at a time and stir for a minute before adding more until you get the right consistency. You will need around 1-2 tsp of slurry per portion for this curry.