1. Preheat oven to 450 degrees. Line baking sheets with parchment paper.
2. Thaw both pie crusts according to package directions, and Unroll onto a lightly floured work surface. Using a rolling pin, gently roll the dough until it has increased approximately 1 inch, from 11 1/2 to 12/12 size. Cut 16 large hearts using the 3 inch cookie cutter, and 16 small hearts using the 2 1/2 inch cookie cutter. Re-roll the dough as needed.
3. Place the smaller hearts on the parchment lined cookie sheets. Spoon Nutella into a plastic sandwich bag and snip off one end with a pair of scissors. Squeeze Nutella onto each pastry heart, into the shape of a heart, leaving approximately 1/4 inch of dough around the edges.
4. Whisk egg white and water into a small bowl. Using a pastry brush, gently brush the egg wash around the edge of the heart. This will help seal the hearts together. Do just a few at a time, otherwise the egg wash will dry. Place a large heart on top, and use a fork to seal and crimp the edges.
5. Brush the top of each ravioli with the remaining egg wash and sprinkle with sugar. Bake for 8 - 9 minutes until golden brown. Prepare Raspberry Sauce.
Raspberry Sauce Thaw the frozen raspberries completely. Puree in a blender or food processor. Run the pureed raspberries through a fine sieve to remove the seeds. Catch the puree in a bowl. Whisk in the sugar until dissolved. You can prepare this sauce in advance, and store refrigerated in an airtight container for up to 24 hours.