Pat scallops completely dry with paper towels — this is essential for a proper sear. Season both scallops and shrimp with salt and pepper.
Heat olive oil in a large skillet over high heat until smoking. Add scallops in a single layer — do not move them. Sear for 2-3 minutes per side until a deep golden crust forms. Remove and set aside.
Add ½ tablespoon olive oil to the same pan. Cook shrimp for 1-2 minutes per side until pink and slightly charred. Remove and set aside.
Reduce heat to medium. Add butter and garlic, sauté for 30 seconds until fragrant.
Stir in gochujang, soy sauce, honey, and red pepper flakes. Cook for 30 seconds to develop the flavors.
Pour in heavy cream and stir to combine. Simmer for 2 minutes until slightly thickened.
Return scallops and shrimp to the pan, tossing gently in the sauce. Cook for 1 minute to coat everything.
Drizzle with sesame oil. Garnish with green onions and sesame seeds. Serve immediately over steamed rice.