about 1 to 2tablespoonice-cold water (as necessary)
1tablespoonsugar(optional for sweet pastries)
To make the pie dough
Start by cutting the butter in cubes.
In a bowl mix the flour, baking powder, salt, and sugar (if using). Add the butter cubes and work the flour into the butter with your hands. Flatten each chunk of butter between your thumb and forefinger. Add the sour cream and mix to moisten the dry ingredients with the sour cream. Knead the dough together adding ice water by the teaspoon only if necessary for the dough to hold together. Place the dough onto a sheet of plastic wrap, and press into a disk as you close the plastic wrap around the dough. Place the dough in the refrigerator to chill for 30 minutes.
Once the dough has chilled, place it into a lightly floured piece of unbleached parchment paper. Sprinkle the dough lightly with more flour, and roll it out into a rectangle that is about 1 inch thick. Now fold the dough over on itself