Preheat the oven to 400°F

1. Season the salmon with salt and pepper.  Place it on a baking sheet and cook for 15-18 minutes until cooked through. Remove from the oven and allow it to cool completely. 
2. Lightly dust a work surface with the flour.  Roll out the puff pastry into a 12-inch by 16- inch rectangle.  Transfer the dough onto a 9×13 rimmed baking sheet.  Fold the edges of the pastry under slightly to create a double layered crust around the perimeter. The pastry should still be slightly hanging over the edge.
3. Whisk the egg white with about a teaspoon of water. Brush the egg white all over the surface of  the puff pastry.  Scatter everything bagel spice all over the crust. 
4. Use a fork to prick the surface of the pastry.
5. Bake for about 20 minutes. Remove the pastry from the oven and if the pastry has puffed up in the middle, use a spatula to press it down.
6. Add the flaked salmon to the pastry crust along with the red onions. Place scant teaspoon amounts of cream cheese in and around the salmond and onions.
7. Whisk together the 10 eggs (plus one egg yolk) with the heavy cream. Add the dill, cayenne pepper and salt and whisk to combine. Pour the egg mixture into the pastry crust. Bake for about 20 minutes until the quiche is set.  If the crust is browning too fast, cover it with some foil. Remove the quiche from the oven and let it coole for 10 minutes.
8. In the meantime, combine the parsley, capers, lemon zest and juice and olive oil. Season with salt and pepper and toss to combine. 
9. Serve the quiche and garnish with the parsley caper salad.