Prepare all the vegetables as per instructions above. As we are using the entire leeks, make sure you clean them really thoroughly from any grit that might be hiding in the green parts.
Heat clarified or regular butter in your Instant Pot using Sauté function (it should be set on High, 30min) and fry thinly sliced leek for 5-8 minutes until soft and translucent but not coloured. Make sure you stir now and again to prevent leek catching.
Add a little bit of stock just to deglaze the pot (use wooden spoon to make sure nothing is stuck to the bottom). Turn the pot off by pressing Keep Warm/Cancel button.
Add all your remaining vegetables: cauliflower, potato, garlic and bay leaves. Pour in the stock and give everything a little mix. Try and prod your chopped veggies so that they sit in the stock and don't protrude out too much (a little bit is fine).
Put on the lid and lock it in place making sure that the black, steam releasing valve is pointing to "Sealing". Set your Instant Pot to "Manual" setting for 8 min on high pressure. It will take approx. 10 minutes for the pot to come to pressure if you've used cold stock (less if you used hot).
When the time is up turn the pot off by pressing Keep Warm/Cancel button and do Quick Pressure Release (QPR) by moving the black, steam releasing valve to "Venting". Please take care during this process.
Remove bay leaves and puree until smooth using stick blender.
Add grated cheese and mix it in with a spoon letting it melt. You might need to turn the "Sauté" function on briefly to make sure your soup is nice and hot for your cheese to melt. That shouldn't be necessary as long as you pureed your soup straight after QPR and added your cheese after pureeing.
Adjust consistency as per your liking by adding few splashes of full fat milk if you think the soup is too thick. Taste and adjust seasoning as required. Serve with your favourite garnishes and enjoy!