Using the blade attachment for your food processor, place flour, sugar and salt in the processor bowl. Process until combined, about 5 seconds. Add the cold butter pieces and process until mixture looks like coarse meal. Add the cold water 2 Tablespoons at a time until dough just comes together. Turn the dough out onto a lightly floured clean surface and knead until it comes together. Divide dough into 2 pieces, form each half into a flat disk. Wrap each disk in plastic wrap and refrigerate for 30 minutes. Roll each disk out into a rectangle to fit the 9 x 13 inch pan about 1/4 inch thick. This doesn't have to be perfect. Your just going to lay it on top of the filling, no crimping needed. Place rectangles on 2 parchment lined baking sheets and refrigerate to chill. Each rectangle will have it's own parchment lined baking sheet.