Heat the butter, oil and garlic in the cooker on the SAUTÉ setting. Sauté the garlic until soft, but not brown, about 2 minutes.
Stir in the rice, making sure to coat it thoroughly.
Pour in the stock and heavy cream. Close and lock the lid of the cooker and set the regulator knob to PRESSURE.
Set the cooker to Pressure Cook HIGH for 6 minutes and press START.
When done, release pressure but allow the risotto to rest on the Warm function with the lid on for about 5 minutes.
Open the lid, stir in the Gruyere and Parmesan, and add salt to taste. Serve immediately.