Pat the shrimp dry with paper towels, then season on all sides with Kosher salt and black pepper.
Heat neutral oil in a large skillet over medium-high heat. When hot, add shrimp and cook on the first side, or until the shrimp turns opaque. Flip, then cook. Transfer to a plate.
To the same pan, melt unsalted butter, then add chopped shallot and season with Kosher salt. Cook, stirring occasionally, until translucent. Add chopped fresh basil, chopped sun-dried tomatoes, cloves of garlic, dried oregano, and crushed red pepper flakes. Cook.
Stir in tomato paste, breaking up with a spatula until dissolved, then pour in seafood stock. Cook, allowing the stock to reduce by about half. Bring to a boil, then reduce the temperature to a simmer. Stir in mascarpone cheese and grated Parmesan, then add fresh spinach. Taste and adjust seasoning as needed.
Return the shrimp to the pan. Garnish with additional fresh basil and capers, then serve immediately with a pinch of flaky sea salt!