Heat a large wok or frying pan over high heat. Add canola oil & shrimp. Stir-fry 1 to 2 minutes until they just change color; remove from pan.
Add sesame oil, galangal, garlic & chilies to same wok; stir-fry 1 minute until fragrant.
Add sugar, soy sauce & fish sauce; stir until sugar dissolves.
Add mussels & stir-fry until they’re coated in the mixture. Cover & cook 2 minutes or until they’re starting to open.
Return shrimp to wok with, pepper & mushrooms. Stir-fry for 1 minute or until mussels are open & shrimp are hot. Remove & discard slices of galangal.
Add green onion & basil leaves; stir-fry until combined.