In a large pot of salted boiling water, cook the linguine according to package instructions until al dente. Reserve 1 cup of pasta water, then drain and set aside.
In a large skillet over medium heat, melt the butter and olive oil together. Once melted, add the minced garlic and sauté for about 1 minute until fragrant but not browned.
Add the shrimp to the skillet, seasoning with red pepper flakes, salt, and pepper. Cook for about 2-3 minutes on each side until the shrimp turn pink and are cooked through.
Stir in the lemon zest and lemon juice, mixing well to combine the flavors. If the mixture seems too thick, add reserved pasta water a little at a time until you reach your desired consistency.
Add the drained pasta to the skillet, tossing gently until the pasta is well coated with the shrimp and sauce. Adjust seasoning if necessary.
Plate the scampi into serving bowls, sprinkle with fresh parsley, and garnish with lemon slices.