Cacio e Pepe with Sauteed Shrimp

Our favorite seafood "peel and eat" takes on a new life thanks to one kitchen-friendly formula: shrimp + starch + sauce = Delicious
Prepare the pasta according to the directions on the package, adding 2 tablespoons of salt to the water. Drain and leave 1 1/2 cups of water to cook.Melt 2 tablespoons of butter in a large skillet over medium-high heat. Add the prawns and cook, stirring occasionally, until the prawns are pink, about 3 minutes. Add the garlic and cook, stirring frequently, for 1 minute. Remove the shrimp mixture, leaving the drippings in the pan.Add 1 cup of water and the remaining 2 tablespoons of butter to the pan and bring to a boil over high heat. Reduce heat to low; add Grana Padano and ground black pepper. Cook, stirring frequently, until the cheese is melted and the sauce thickens, about 1 minute.Add the cooked pasta and shrimp mixture and stir to coat, adding the remaining 1/2 cup pasta water as needed for the desired consistency. Remove from the heat; add the pecorino, zest and juice and mix until smooth. Spread evenly over 6 plates. Sprinkle with the remaining 1/2 teaspoon salt and garnish with ground black pepper. Serve immediately.