Toss shrimp with 1 Tbsp. sherry and 1 Tbsp. soy sauce in a bowl; marinate about 10 minutes. Transfer shrimp to a plate; discard marinade.
Mix broth, remaining 1 Tbsp. sherry, remaining 1 Tbsp. soy sauce, vinegar, sugar and cornstarch. Heat 2 tsp. oil in wok or large nonstick skillet over high heat. Add shrimp, peanuts, and pepper flakes; cook til shrimp are nearly opaque, 1 to 2 minutes. Transfer shrimp mixture to a plate.
Cook bell pepper in remaining 2 tsp. oil in wok til it begins to soften, 1 to 2 minutes. Add scallion whites, garlic, and ginger and cook til fragrant, 30 seconds. Stir in broth mixture and shrimp mixture and cook til sauce is thick and syrupy, about 1 minute.
Stir in scallion greens and serve. Serve with fried rice.
Note: Adjust the amount of pepper flakes to suit your taste.