Heat the olive oil in a large skillet over medium-high heat. Season the cod fillets with salt and pepper, and sear them for about 4 minutes on each side until a golden crust forms. Remove and set aside.
In the same skillet, sauté the minced garlic for 1 minute until fragrant.
Add the heavy cream and chicken broth, stirring to combine. Bring to a simmer.
Stir in the grated Parmesan cheese until it melts into the sauce.
Add the sun-dried tomatoes and Italian seasoning. Allow the sauce to simmer and thicken slightly for 3-4 minutes.
Mix in the baby spinach and cook until wilted, about 2 minutes.
Return the cod fillets to the skillet, nestling them into the sauce. Simmer for another 3-4 minutes, spooning the sauce over the cod until heated through and fully cooked.
Taste and adjust seasoning as needed.