Defrost enough large shrimp for two people. Quickie method: place frozen shrimp in bowl of cold water for 15 minutes. Rinse under water to completely defrost. Drain well, and set aside.
Slice a few cloves of garlic into slivers. Chop a tablespoon or so of parsley. Strip off some Rosemary leaves. Add to shrimp, along with some red pepper flakes, olive oil, and salt and pepper. Toss.
Heat some olive oil in a nonstick pan to very hot. Add shrimp and arrange in a single layer. Let shrimp sear a few minutes on each side, allowing them to take on a little char. Toss in the pan one last time and serve.