1. Start by patting the shrimp dry with paper towels. This helps them to sear nicely in the pan.
2. Heat the olive oil in a large skillet over medium-high heat. Once the oil is shimmering, add the garlic and red pepper flakes. Sauté for about 30 seconds, just until the garlic is fragrant.
3. Add the shrimp to the pan in a single layer. Let them cook undisturbed for about 2 minutes.
4. Flip the shrimp and add the lemon zest and juice. Cook for another 2-3 minutes, or until the shrimp are pink and opaque.
5. Season with salt and pepper to taste, and stir in the parsley. If desired, add a pat of butter for a little extra richness.
6. Remove from heat and serve immediately, garnished with extra lemon slices if you like.

Remember, the key to perfectly cooked shrimp is not to overcook them. They should be firm to the touch but not rubbery. A trick I learned from my mom is to keep an eye on the tails; once they curl inwards, you’re just about there.