Line a large baking sheet with parchment paper. Set aside.
OPTIONAL: To butterfly shrimp, insert a knife about three-quarters of the way into the shrimp at the top. Cut a slit down the centre of the shrimp's back to the tail. Use your fingertip to open the flesh of the shrimp slightly. They don't need to be flat. Season with salt and pepper, set aside.
In one shallow bowl, add 1/2 cup flour for dredging. In another shallow bowl, whisk the batter ingredients together until combined. The batter should resemble pancake consistency. If too thick, add a little extra beer or mineral water, whisking between each addition. In the third bowl, mix together the shredded coconut and bread crumbs.
Dredge in the flour (shake off excess), dip in the batter (shake off excess) and coat in the breadcrumb/coconut mixture. Lightly press the coconut onto the shrimp.
Place onto prepared baking sheet and repeat with remaining shrimp. Arrange shrimp in a single layer and freeze until firm (about 30-45 minutes).
In a dutch oven or deep skillet, heat vegetable oil (about 2-3 inches deep in the pot) until nice and hot.
Fry the FROZEN shrimp in batches for about 2-3 minutes on each side or until golden brown and crispy. Drain them on a paper towel lined plate.
Serve immediately with sweet chili sauce.
Notes
Frying frozen shrimp ensures they do not overcook, while giving the crumb time to develop into that delicious golden colour. The coating adheres better and doesn't fall apart.If you don't have time to freeze them, you can still go ahead and fry them up as soon as you've finished breading them. Just keep in mind the crumb may begin to fall apart after a minute of cooking.