To devein shrimp: Pat the shrimp dry on both sides, then use a paring knife to make a shallow cut along the back of the shrimp. Once exposed, use the paring knife to pull out and discard the dark vein.
Setup the breading station. Grab 3 shallow bowls. In the first bowl, place ½ cup (60g) flour, 2 tsp kosher salt, 1 tsp garlic powder, and ¼ tsp black pepper, then stir to combine. In the second bowl, place 3 whisked eggs. In the third, mix together 1½ cups (150g) panko breadcrumbs and ½ cup (50g) grated Parmesan.
Heat the oil. Add enough neutral oil in a large skillet to coat the bottom by about ¼-inch. Heat over medium-high until the oil is hot and reaches 375°F (190°C).
Bread the shrimp. Dredge each shrimp fully on both sides in flour. Shake off any excess, then transfer and coat in eggs. Finally, move the shrimp to the breadcrumbs, coating evenly on all sides. Place on a wire rack until ready to cook. Repeat with remaining shrimp.
Pan-fry the shrimp. Once the oil is hot, you’ll work in batches to fry the shrimp. Carefully lower breaded shrimp into the oil, leaving an inch or so of space in between. Cook for 2-3 minutes per side, or until they turn golden brown. Use tongs to flip each shrimp over, then cook for 2 minutes more. Immediately transfer to a paper towel lined wire rack, sprinkle with a pinch of kosher salt, then repeat until all shrimp are cooked.
Add sauce and cheese. Preheat a broiler to high with a rack set 4-6 inches below. Spread about 1 cup (250g) of the marinara sauce on a rimmed baking sheet (or in a large skillet), then place the pan-fried shrimp in a single layer on top. Spoon a little bit of the remaining marinara sauce on top of each shrimp. Layer thin slices of mozzarella cheese on top, then sprinkle with the remaining 2 Tbsp grated Parmesan. Transfer to the broiler, then cook for about 5 minutes, or until the cheese is melted and golden brown. Keep an eye on the shrimp so they don’t burn and rotate the pan halfway through.
Finish, then serve! Garnish immediately with a few tablespoons of chopped fresh parsley. Enjoy immediately!