Instructions

Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, 5 to 10 minutes. Drain on paper towels, reserving grease in the skillet.
Place cauliflower in a metal or silicone steamer basket inside a multi-functional pressure cooker (such as Instant Pot(R)). Add 1 cup water to the pot. Close and lock the lid. Select Steam function; set timer for 4 minutes. Allow 10 to 15 minutes for pressure to build.
Release pressure carefully using the quick-release method according to manufacturer's instructions, about 5 minutes. Unlock and remove the lid.
Drain cauliflower and transfer to a deep bowl. Add Parmesan cheese, butter, MCT oil, vinegar, and salt. Mix with an immersion blender until smooth. Stir in diced bacon. Add 1 to 2 tablespoons of the reserved bacon grease.