Mix together the flour and seltzer.
Place the broccoli in a large bowl and pour the batter over the broccoli. Allow to sit in the batter for 15 minutes, mixing every five minutes to allow the broccoli to get fully coated in the batter.
Then dip each piece of broccoli in the breadcrumbs, so that it is fully covered.
Line a baking sheet with parchment paper, then place cooling racks on the baking sheet. Spray, and place the broccoli on the cooling racks, making sure to leave space between each piece. Spray with cooking spray and bake at 450 degrees Fahrenheit for 30 minutes.
Serve with your favorite dipping sauce.