In a bowl, season shrimp lightly with salt and pepper.
Heat oil in a large skillet over medium-high heat. Add 2 tbsp. of butter. Add shrimp and cook for 3 minutes, tossing and flipping through process. Remove shrimp and let rest on plate.
Deglaze pan with mirin.
Add 4 tbsp. of butter. Once melted, add onion and sauté for 2 minutes. Add carrots and sauté for an additional 3 minutes.
Reduce heat to medium. Push carrots and onions to edge pan, forming a well in the center. Add sesame oil to the center. Then add eggs. Scramble eggs with carrots and onions for 1 minute.
Stir in cook rice. Season lightly with salt and pepper. Then, season liberally with garlic powder. Add soy sauce and oyster sauce. Stir contents together and keep stirring until rice is brown in color.
Add frozen peas and corn. Continue to stir until peas and carrots are warm.
Add cooked shrimp and toss.
Garnish with green onion, and serve warm immediately.