Preheat oven to 375 degrees. Roll pate brisee to 1/8-inch thickness on a lightly floured surface. Fit into a 9-inch pie dish, and trim edges, leaving a 1-inch overhang. Tuck overhang under so edges are flush with rim, and crimp edges. Prick bottom of dough with a fork. Freeze for 15 minutes. Line dough with parchment, and fill with pie weights or dried beans. Bake until edges begin to turn gold, 25 to 30 minutes. Remove weights and parchment. Bake until crust is light gold and cooked through, 10 to 15 minutes. Let cool on a wire rack.
Reduce oven temperature to 350 degrees. Whisk flour and 1/2 cup sugar in a medium bowl. Add egg and cream, and whisk to combine. Toss raspberries, remaining 1/4 cup sugar, and the salt in a medium bowl. Spoon berries into crust, then pour in cream mixture, filling to just below the rim.
Bake until custard is set but still a bit wobbly in the center, about 45 minutes. Let cool in dish on a wire rack. Cover, and refrigerate for at least 2 hours (or up to 1 day). Garnish with fresh raspberries, and serve cold.