To begin with, place the steel insert, switch on the IP and press "Sauté" button.
Heat olive oil, add chopped garlic and fry until just golden and aromatic.
Add chopped onion and cook until it softens.
Add diced potatoes and chopped celery and fry for 30 seconds.
Add Dijon mustard, salt, pepper, stir in the chicken stock or vegetable stock and apple cider vinegar.
Add bay leaves and sprigs of thyme, cover and seal the pot.
Set the pressure cook time to 10 minutes on "High".
Once the cooking times is over, quick release the pressure.
Open the pot and discard thyme and bay leaves.
Using immersion blender, carefully purée the soup until creamy. Leave some small chunks of potatoes in it.
Stir-in the Parmesan and Sharp Cheddar and adjust the seasonings if needed.
Pour hot soup in individual bowls, garnish with your favorite toppings and serve hot.