Preheat oven to 410°F (210°C). Lightly spray an oven tray with cooking oil spray; set aside.
Whisk the egg in a small shallow bowl. Add in the flour, beer, garlic powder, salt and water. Whisk slowly until all the ingredients come together; then beat until the batter is smooth. Pat dry each prawn/shrimp until they are completely dry.
Holding the shrimp/prawns by the tail; dip one shrimp/prawn at a time into the batter to evenly coat; gently shake off any excess; then evenly coat them in the breadcrumbs. Place them onto the oven tray in a single layer.
Bake for 10 minutes on one side; flip them and bake for a further 8-10 minutes, or until cooked through (depending on the heat in your oven).
Notes
The trick to making these crispy shrimp taste like they were deep fried is a spray of oil before going in the oven. Trust me and try it!