In a food processor bowl add flour, salt, baking powder, caraway seeds and butter. Pulse until the butter in broken down and crumbly. Add sour cream and pulse until just starting to pull away from sides. With processor running, add water and mix until just combined. Dump out dough onto a sheet of plastic wrap and form into a flat disc and wrap with plastic wrap. Mixture may still appear crumbly when dumping out onto plastic wrap, however once you start to form the dough it will start to come together. Chill for at least an hour, but can be done a day in advance. Let sit at room temperature for 20 minutes prior to rolling.