Preheat oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish.

In a large skillet, heat 1 tbsp olive oil over medium-high heat. Add the minced garlic and sauté for 30 seconds until fragrant. Add the shrimp and cook for 2-3 minutes, stirring occasionally, until they just start to turn pink. Remove shrimp from skillet and set aside. Do not overcook.

In the same skillet (no need to clean), melt 1/4 cup unsalted butter over medium heat. Whisk in the all-purpose flour and cook for 1-2 minutes, stirring constantly, to create a roux. Gradually whisk in the whole milk and chicken broth until smooth. Bring to a gentle simmer, whisking frequently, until the sauce thickens, about 3-5 minutes.

Reduce heat to low. Add the softened cream cheese cubes and whisk until completely melted and smooth. Stir in the grated Parmesan cheese, shredded sharp cheddar cheese, Dijon mustard, fresh lemon juice, salt, and black pepper. Stir until cheeses are melted and the sauce is smooth and creamy.

Gently fold the partially cooked shrimp into the cheese sauce. Pour the shrimp mixture into the prepared 9x13 inch baking dish, spreading evenly.

In a small bowl, combine the panko breadcrumbs, 2 tbsp melted butter, garlic powder, and paprika. Mix well until the breadcrumbs are evenly coated.

Sprinkle the breadcrumb topping evenly over the shrimp mixture in the baking dish. Bake for 20-25 minutes, or until the casserole is bubbly around the edges and the topping is golden brown and crispy.

Remove from oven and let stand for 5 minutes before serving. Garnish with fresh chopped parsley, if desired. Serve hot.