The biggest secret is patting the shrimp completely dry before searing; wet shrimp steam and turn rubbery. Don't crowd the pan, and pull the shrimp out while they are slightly underdone — residual heat finishes the job. Store leftovers in an airtight container in the fridge for up to 2 days and reheat gently in a skillet. Freezing cooked shrimp is not recommended. For dairy-free, swap the butter for olive oil or plant-based butter. For a spicier version, double the red pepper flakes and add a pinch of cayenne. For kids, reduce the garlic to 3 cloves and skip the red pepper flakes.