If using frozen shrimp thaw them overnight in the refrigerator. Drain shrimp and pat dry.
Zest one large lemon and then squeeze the juice to yield at least 2 T juice and close to 1 T lemon zest.
Finely mince garlic cloves to make 2 T minced garlic.
Heat the olive oil over medium high heat and then melt the butter, using a large heavy pan. (I used a pan that was nice enough to serve the shrimp from, which helps keep them hot.)
Add the shrimp in a single layer and cook just until they start to turn pink at the edges, not more than 1 to 2 minutes.
Turn shrimp over quickly and add the minced garlic. Continue to cook until shrimp are barely firm and slightly pink, probably not more than 3 to 4 minutes more. (Don’t overcook; the shrimp will continue to cook a little in the hot pan.)
Turn off heat and add the lemon juice, lemon zest, and salt as desired and stir to coat shrimp.
Serve immediately.
