There’s no worry about this banana bread drying out at the edges, given the pot’s steamy environment. Here are the two secrets to success: First, make sure that pan is sprayed well, very nicely coated. If you think you’ve sprayed it enough, spray it a little more. The cake can stick like mad in the corners and indentions of the Bundt pan. And second, make sure the bananas as truly ripe, beyond the point you’d slice them onto cereal.
Pour the water into a the cooker. Set a heat- and pressure-safe trivet into the pot. Generously spray the inside of a 7-inch Bundt pan with baking spray, making sure the flour and fat mixture gets into all the crevices. Make an aluminum foil sling and set the pan in the middle of it.
Put the sugar, eggs, butter, and bananas in a food processor. Cover and process until smooth, stopping the machine once to scrape down the canister. Add the yogurt, lemon juice, and vanilla. Cover and process until smooth. Stop the machine and scrape down the inside.
Add the flour, baking soda, and salt. Cover and pulse until a uniform batter forms. Add the nuts and pulse to chop a bit and blend them in.
Pour, dollop, and scrape the batter into the prepared pan. Use a rubber spatula to smooth the top of the batter. Use the sling to pick up the pan and set it on the trivet in the pot. Fold down the ends of the sling so they fit into the pot without touching the batter. Lay a large paper towel over the top of the cake to cover it without touching the batter below. Lock the lid onto the cooker.
Optional 1Max Pressure Cooker Press Pressure cook on Max pressure for 18 minutes with the Keep Warm setting off.
Optional 2All Pressure Cookers Press Meat/Stew or Pressure cook (Manual) on High pressure for 25 minutes with the Keep Warm setting off.
When the machine has finished cooking, turn it off and let the pressure return to normal naturally, about 25 minutes. Unlatch the lid and open the cooker. Remove the paper towel, then use the sling to lift the Bundt pan out of the cooker and onto a wire cooling rack. Cool for 5 minutes, then invert the pan onto a plate and shake gently to release the cake onto a cutting board. Slip the cake back onto the wire rack and continue cooling for at least 20 minutes before slicing into wedges.
• This recipe works in a 3-quart cooker as written; a 7-inch Bundt pan will just fit. Make sure the paper towel doesn’t catch on the rim of the lid. The amount of batter will rise up and almost touch the top of the cooker. It can get a little wet around the edges, but we didn’t mind this in testing. For pitch-perfect aesthetics, when you fill the Bundt pan, leave a 1/2 inch space between the top of the batter and the top of the pan. (Discard that little bit of leftover batter.)
• Substitute any nut you like—pecans, almonds, skinned hazelnuts.
• Scrape the batter from the food processor into a bowl, then fold in up to 1/2 cup raisins, dried cranberries, or semi-sweet chocolate chips before getting the batter into the pan.
• A baking spray is easiest for getting the fat-and-flour mixture into every crevasse of a Bundt pan. But feel free to go old-school, using butter and all-purpose flour to coat the inside of the pan.