Grease and flour the Bundt pan and set aside.

Make flax egg by whisking ground flaxseeds with 3 tablespoons of water until gelatinous. Allow to sit for 5 minutes.

Peel and mash bananas in a medium bowl. Add flaxseed mixture, oil, sugar, vanilla, salt, baking soda, and mix well.

Add flour and combine until just mixed.

Pour batter into the greased pan. Cover gently with a paper towel, then secure aluminum foil over the paper towel around the rim. Add 1 cup of water to the Instant Pot. Place the pan on the trivet and gently lower into the pot. Close Instant Pot lid with pressure valve to sealing.

Select Manual/Pressure Cook (Hi) and adjust cook time to 50 minutes. Allow 10 minutes of natural pressure release.

Open the Instant Pot, carefully lift the trivet with the pan, and remove. Allow banana bread to cool for 5 minutes, then flip onto a plate.