Give the shrimp a quick rinse with water then pat dry with paper towels. Using kitchen scissors, cut the back of the shrimp, through the shell, to expose the vein then remove the vein.
In a large bowl, add cleaned shrimp, cornstarch, smoked paprika, garlic powder, cayenne powder, salt and pepper and mix well. Make sure to coat each shrimp evenly in the seasoning.
In a large pan, heat olive oil and 2 tablespoons of butter over medium heat. Add the shrimp in a single layer then cook for 2-3 minutes on each side, or until pink and opaque. Remove the shrimp from pan and set aside. Repeat with remaining shrimp if needed.
Add in remaining butter (3 tablespoons) and garlic and saute until the garlic is fragrant, about 1 min. Add lemon juice and quickly stir. Add the shrimp back in and quick toss to coat evenly. Turn off heat and sprinkle chopped parsley on top
Serve immediately with rice or pasta and wedges of lemon.