Pat salmon fillets and shrimp thoroughly dry with paper towels. Mix paprika, garlic powder, salt, and pepper in a small bowl. Rub the seasoning evenly over both sides of the salmon and shrimp.

Heat olive oil in a large skillet over medium-high heat. Add salmon fillets and cook for 3 to 4 minutes per side until golden brown and cooked to desired doneness. Remove salmon and set aside on a plate.

In the same skillet, add seasoned shrimp. Sauté for 1 to 2 minutes per side until pink and opaque. Transfer shrimp to the plate with the salmon.

Reduce heat to medium. Melt butter in the skillet. Add minced garlic and Italian seasoning; sauté for 1 minute until fragrant. Pour in chicken/vegetable broth and lemon juice, scraping up any browned bits on the pan bottom with a wooden spoon. Let liquid simmer for 2 minutes to reduce slightly.

Reduce heat to low. Whisk in heavy cream and grated Parmesan cheese. Simmer gently for 3 to 4 minutes until the sauce thickens into a velvety consistency.

Return cooked salmon and shrimp to the skillet, spooning cream sauce over top. Arrange fresh lemon slices around the pan. Simmer on low for 1 to 2 minutes until warm. Garnish with fresh chopped parsley and extra black pepper before serving.