Cream butter and brown sugar until smooth.
Add in raisins, carrot, potato and egg and stir until combined.
Stir in flour and baking soda.
Grease two small glass bowls or one large bowl and fill with pudding, leaving about an inch between the top of the pudding and the top of the bowl to give it room to rise.
Cover the bowl with parchment paper or an upsidedown plate, then wrap with plastic wrap in a double layer, sealing tightly to keep excess moisture out.
Pour two cups of water into the insert of the Instant Pot. Place the trivet in the insert, and put the uncovered bowl of pudding on the trivet. Pro Tip: Create a foil sling to easily pull out the pudding from inside the Instant Pot.
Cover with the lid and leave the sealing valve open so it can vent. Press the Saute function.
Once the cooker starts to steam, press the “Adjust” button, which allows you to change the Saute setting to low.
Steam the pudding on low for 15 minutes.
After steaming, seal the release valve of the Instant Pot and press “Cancel.” Then select “Pressure Cook” and set it to cook on high pressure for 35 minutes.
Once the cycle is complete, let naturally release for 30 minutes or up to 1 hour.
Carefully lift the pudding out of the Instant Pot using the foil sling (be careful; the sides of the pot will still be hot).
Remove the plastic wrap and plate and run a knife around the top edge to help the pudding release from the sides of the bowl before inverting on a plate.
Serve hot with brown sugar sauce and enjoy (directions for sauce below)!