Prep the garlic: Place the separated cloves in a bowl, cap with another bowl, and shake ~30 seconds to loosen skins. Peel and finely mince (a pinch of salt helps anchor for faster mincing).

Make garlic butter: Melt 4 Tbsp butter in a sauté pan over medium heat. Add minced garlic; cook 2–3 minutes, stirring, until pale golden and fragrant (don’t brown). Transfer garlic butter to a small bowl; keep the pan for searing.

Season & coat shrimp: Pat thawed shell-on shrimp very dry. In a small bowl, mix rice flour, paprika, kosher salt, cayenne. Sprinkle over shrimp; toss gently until evenly coated.

Sear in batches: Heat 2 Tbsp olive oil in the same pan over medium-high. Add shrimp in a single, uncrowded layer; sear 2–3 minutes per side until browned and just opaque. Spoon in some garlic butter during the last 30 seconds to glaze. Transfer to a warm platter; repeat with remaining shrimp and garlic butter (add a teaspoon of oil between batches if pan looks dry).

Serve: Pile shrimp on a warm platter and drizzle with extra garlic butter. Optional squeeze of lemon brightens the butter and balances the spice. Serve immediately—peel-and-eat!