Add 3 tsp of oil to the inner pot and use kitchen roll to rub the base of the inner pot.
Add the quinoa to the pot with the water and salt and give it a stir.
Lock the lid in place, and select Pressure Cook on ‘High’ and program the time for 1 minute, then press Start.
Once the program has finished, allow the pressure to release naturally for 10 minutes, then quick release any remaining pressure.
Gently fluff the quinoa with a fork, then remove from the inner pot, and set to one side.
Give the inner pot a quick clean to remove any quinoa stuck to the bottom, and then select the Sauté program and adjust the time to 8 minutes.
Once the pot starts to warm up, add the remaining 3 tsp of oil with the chopped onions and garlic, and sauté for about 4 minutes until soft.
Add the aubergine, peppers, and courgette and sauté for a further 2 minutes, stirring constantly.
Next, add the balsamic vinegar, tomato puree and spices and give it one last stir before adding the stock. Press Cancel and use a wooden spoon to deglaze the base of the inner pot to make sure nothing is stuck.
When the base has been deglazed, add the chopped tomatoes on top but do not stir, then secure the lid.
Select Pressure Cook on ‘High’ and program for 3 minutes.
Once the program has finished, perform a quick pressure release and when the valve drops, remove the lid and press Cancel.
Give the vegetables a stir, then select Sauté again and reduce any excess liquid by a quarter.
Turn off the Instant Pot then, stir in the cooked quinoa and olives and leave to stand for a few minutes before serving garnished with basil leaves.