Grease a small, 6 cup bundt pan with cooking spray and set aside.
In a small mixing bowl, add flour, baking powder and salt and mix well.
In a larger mixing bowl, combine butter and sugar. Use a pastry blender to cut the butter into the sugar until small pea size pieces remain. Add egg and mix well.
Add flour and milk, alternating between the two and mix well. Fold in fresh blueberries.
Pour batter into pan and spread evenly.
Place paper towel and foil over the top of the pan. Make a foil sling by folding a long piece of foil in half and and place under the bundt pan, pulling it up on the sides.
Place 1 cup water into the instant pot and place the trivet into the bottom of the pot. Place the bundt pan and sling inside the pot.
Close the instant pot and seal the pressure valve. Set the instant pot on manual, high pressure for 35 minutes. Let the pressure release naturally for 20 minutes. Carefully remove from instant pot and remove paper towel and foil cover.
Let cool for 10 minutes before inverting the pan and removing the cake. Let cool completely before frosting.
To frost, microwave icing for 15 seconds and stir. Continue to microwave in 10 second intervals (if necessary) stirring after each interval until the consistency is that of a drizzle. Drizzle icing over coffee cake and slice to serve.