In a medium bowl, combine the Cajun seasoning, garlic powder, onion powder, black pepper, and salt. Add the shrimp and toss to coat evenly. Let marinate for 15 minutes.

Set up a breading station: Place the flour in one shallow dish, the beaten egg in another, and the panko breadcrumbs in a third.

Dredge each shrimp in the flour, shaking off the excess, then dip in the egg, and finally coat with panko breadcrumbs. Press gently to adhere.

In a large skillet, heat the vegetable oil over medium-high heat. Once hot, add the breaded shrimp in a single layer (you may need to do this in batches). Fry for about 2-3 minutes on each side until golden brown and crispy. Remove and drain on paper towels.

In a separate saucepan, combine the heavy cream, Dijon mustard, and lemon juice over medium heat. Stir until warmed through and slightly thickened.

Serve the crispy shrimp drizzled with the creamy sauce and garnish with chopped parsley.