In a large skillet over medium-high heat, add 2 tablespoons butter and olive oil and heat until butter is melted. Stir in the garlic and lemon zest until fragrant, about 30 seconds.
Stir in the wine, red pepper flakes if using, and salt and pepper to taste (I like 1 teaspoon salt and 1/2 teaspoon pepper). Bring to boil. Add the shrimp, cover, and cook until the shrimp are slightly translucent, about 2 minutes.
Reduce the heat to medium and cook until the shrimp are just cooked through, about 2 minutes longer. Remove from heat and stir in lemon juice and remaining 2 tablespoons butter. Season to taste with salt and pepper and garnish with parsley.
Lemon: Zest the lemon before you cut it in half for juice.
White wine: Choose a dry variety such as Pinot Grigio, Chardonnay, or Sauvignon Blanc. Substitute chicken broth or shrimp stock if you want to omit the wine.
Shrimp: For the best flavor, buy individually quick frozen raw shrimp in the shell (pre-cooked shrimp will turn rubbery). Thaw frozen shrimp overnight in the refrigerator or in a bowl in the sink with a trickle of cold water running over them. To clean the shrimp, use a knife to make a shallow slice right through the shell on the shrimp’s back, from its head to its tail. Then pick out the black or green vein that runs along the back and discard it.
Yield: This recipe makes 4 servings from 2 pounds of shrimp. It will feed 6 or 8 as an appetizer.
Storage: This recipe is best enjoyed the day it is made.
Make ahead: The shrimp can be thawed and cleaned up to 24 hours in advance.
Shrimp stock: Consider making homemade shrimp stock from the shells (you can always freeze the shells and tackle that another day).