Pat the prawns dry and season with salt and pepper.
Heat butter and oil in a non-stick skillet over medium-high heat until shimmering.
Add garlic and chilli flakes. Stir constantly for about 10–15 seconds until fragrant and lightly toasted.
Arrange prawns in a single layer, cook undisturbed for 1 minute until the edges turn golden.
Flip prawns and cook for another 1 minute until opaque throughout.
Remove from heat, squeeze over lemon juice and sprinkle parsley. Toss gently to coat before serving.
Notes
Through testing I found slicing garlic paper-thin yields a smooth, nutty sauce without any bitter burnt bits.Use a shallow container to chill leftovers quickly and preserve the prawns’ tender texture.