In a mixing bowl, whisk together flour, baking powder, and salt. In a separate bowl, whisk together the buttermilk, butter, water, eggs, and sugar. Stir this mixture into the dry ingredients until well-combined.
Spread shortening or butter in the bottom and 2 inches up the sides of the Instant Pot® and pour in the batter. Place lid on pot and lock into place to seal. Cook on Low Pressure for 40 minutes. (If your Instant Pot® has a Cake setting, use that instead of Low Pressure.) Let sit for 10 minutes. Use Quick Pressure Release.
To remove pancake, run a rubber spatula around the edge of the pancake. and quickly invert onto a serving plate. Cut into wedges and serve with toppings, of choice.
Variation: For a super quick version of this recipe, use 3 cups of prepared batter from an instant pancake mix. Melt 2 tablespoons butter and stir into batter; proceed with the recipe, starting with the second paragraph.