Crisp Bacon: Place chopped bacon in your Instant Pot, then turn heat to medium (press "Sauté" button). Stir occasionally, then allow the bacon bits to crisp (~4 mins). Remove bacon bits from Instant Pot, then place them on a paper towel to absorb the excess fat.
Sauté Onion, Garlic, Green Onions: Sauté onions in bacon fat for ~1 – 2 mins until softened. Add in garlic and half of the green onions. Season with a pinch of kosher salt and pepper. Sauté until fragrant.
Deglaze: Pour ~⅓ cup (100ml) unsalted chicken stock. Scrub all the brown bits off the bottom of the pot with a wooden spoon (keep the brown bits as they are very flavorful).
Pressure Cook Cauliflower Potato Soup: Add 2 bay leaves, cauliflower, and 2 red potatoes in Instant Pot. Pour the remaining chicken stock in Instant Pot. Close the lid and pressure cook at High Pressure for 3 minutes, then 10 minutes Natural Release. Open the lid carefully.Remove Bay Leaves (Optional): If you don't think your immersion hand blender is powerful enough to blend through the bay leaves, you can remove them at this step.
Blend & Season: Blend cauliflower soup into desired consistency with an immersion hand blender. Add 1 cup (250 ml) of heavy cream. Taste the soup and season with 2 tbsp (30 ml) of fish sauce and kosher salt.
Serve: Garnish with green onions, crispy bacon bits, and freshly grated Parmesan cheese. Enjoy immediately. I think you will love it ;)