Cut the tops out of each of the pie pumpkins. Remove the seeds and strings from the inside of each pumpkin. Set the seeds aside for roasting.
Carefully cut the pie pumpkins into wedges to nestle into the slow cooker and instant pot. Add 1 cup of water to both the slow cooker and instant pot. Add the steaming rack to the instant pot insert.
Place 2 pumpkins worth of wedges into the slow cooker, skin side down. Place 2 pumpkins worth of wedges into the instant pot, on the steam rack.
SLOW COOKER: Slow cook on low for X hours. Once cooked, set out into a single layer to cool down. Then scrape the pumpkin flesh into a bowl and mash to puree. If preferred, puree the pumpkin with a touch of water in a blender. Let cool before adding to containers and freezing to use later. Thaw and use in recipe that calls for pumpkin puree.
INSTANT POT: Set on High Pressure, Manual mode and pressure cook for X minutes. Once cooked, set out into a single layer to cool down. Then scrape the pumpkin flesh into a bowl and mash to puree. If preferred, puree the pumpkin with a touch of water in a blender. Let cool before adding to containers and freezing to use later. Thaw and use in recipe that calls for pumpkin puree.