Press saute and let the display show "Hot". Add the butter to this.
Once the butter melts, add the onion and garlic.
Once the onion has softened (do not let it brown), add the broccoli and carrots to the inner pot. Press Keep Warm / Cancel to turn off Saute mode. Add the vegetable stock to this.
Close the lid of the Instant Pot. Turn the knob to seal. Press Manual, adjust to High Pressure and adjust time to 5 mins.
As soon as 5 mins is done and the Instant Pot beeps, turn the seal manually to release ( watch for the hot steam when you do this) and do a Quick Release of pressure.
Open the Instant Pot and using an immersion blender, blend part of the chunky soup to smoother bits. Keep some of the veggies intact. You can also wait for a few minutes, transfer part of the soup to a blender, blend and pour back to the pot.Add salt, pepper and a few drops of hot sauce.
Press Saute button again. Pour in the heavy cream and mix well.
Once it starts bubbling, add the cheese and mix well.
Keep mixing for 2 mins and switch off the saute setting. You can keep it at Keep Warm mode, till you are ready to serve. But, keep stirring every once in a while to avoid clumping. Also, don't keep it in the Keep Warm mode for more than a few minutes.