Combine shrimp shells, water, soy sauce and bourbon in a sauce pan. Heat to a gentle boil and shells turn pink. Strain liquid into a bowl and discard solids.
Whisk brown sugar, cornstarch and pepper flakes into the soy mixture until cornstarch is dissolved.
Heat oil in a large wok. Stir in shrimp, scallion whites and garlic. Cook until shrimp just turn pink - about 3 minutes.
Add soy sauce mixture and continue to cook until sauce thickens and shrimp are cooked thru - about 3 minutes.
Remove from heat. Stir in scallion greens.
Serve over rice.
