1. Place a large baking sheet in the oven, and preheat oven to 450 degrees.
2. Place shredded squash and onion on a layer of paper towels. Cover with
another layer of paper towels, and press down to remove all
excess moisture. Repeat until squash and onion shreds are as dry as
possible.
3. In large mixing bowl, combine squash, onion, egg whites, flour, and salt. Mix well.
4. Using oven mitts, carefully remove the hot baking
sheet from the oven. Cover sheet evenly with a 3-second spray of non-stick spray.
5. Spoon squash mixture onto the sheet in 12 evenly spaced mounds. Using
the back of a spoon, flatten and spread each mound into a circle about 3
inches wide. Carefully return pan to the oven and bake for 8 minutes.
6. Using oven mitts, carefully remove sheet. Coat the top
of the latkes with another spritz of non-stick spray, gently
flip with a spatula.
7. Return to the oven and bake for 10 minutes, until both
sides of latkes are crispy. Serve topped with scallions.