In a microwaveable bowl, combine raisins and water. Microwave for 3 minutes, then set aside for at least 5 minutes to allow raisins to absorb water.
In a medium bowl, combine butter, sugar, egg, milk and vanilla until uniform.
In a large bowl, stir together flour and baking powder.
Pour butter mixture into flour mixture and stir to combine.
Drain 1/4 cup water from raisins and set aside. Pour raisins and remaining water into dough and mix until a dough ball forms, adding additional water 1 tbsp at a time from the reserve as necessary.
Coat the inside of a 7 inch cake pan with nonstick spray
Pat dough into the springform pan and cover loosely with foil--do not seal.
Pour one cup of water in the Instant Pot and insert the steam rack. Carefully lower the cake pan on to the steam rack.
Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL or PRESSURE COOK function*. Use the +/- keys and program the Instant Pot for 45 minutes.
When the time is up, let the pressure naturally release for 15 minutes, then quick-release the remaining pressure.
Meanwhile, preheat oven on broil for 5 minutes.
When cooking time is up, carefully remove the baking pan from the Instant Pot, discard the foil, and sprinkle 1 tsp sugar over the top.
Set the pan in the preheated oven and immediately turn the oven OFF. Allow the pan to sit in the oven until pan is cool enough to handle, at least 30 minutes.
Release the soda bread from the pan, slice and serve.
Notes
*The MANUAL and PRESSURE COOK buttons are interchangeable