1Combine all ingredients in the Instant Pot and seal. Cook on Manual High Pressure for 5 minutes, then quick release. Remove rosemary sprig and mash with a potato mashed until desired texture. Transfer to a glass airtight container and chill before serving.
2Slowcooker/Crockpot Instructions: Cook on low for 8 hours or high for 4 hours then remove rosemary and mash.