In a large bowl, combine butter and sugar. Mix until light-colored, about 2 minutes.
Add the pumpkin, egg, and vanilla extract, and mix until well-combined.
Make a well in the center and stir together the flour, baking soda, baking powder, salt, and pumpkin spice blend. Using a wooden spoon, mix with the wet batter until just combined.
Place two pieces of paper towel on the bottom outside of a 6″ springform pan and then seal with tinfoil. Grease the inside of the pan and then fill with batter.
Place 1/2 cup of water in the IP and place your trivet in the IP.
Put the pan over the top of the trivet and secure the lid.
Bake at manual for 60 minutes, and then natural release for 5 minutes.