Pat the salmon dry and season with salt and pepper.
Heat olive oil in a large skillet over medium-high heat and sear the salmon for 4-5 minutes per side until golden brown; remove and set aside.
In the same pan, melt butter and sauté the garlic for about 30 seconds.
Add the plum tomatoes and cook for 2-3 minutes until they soften.
Stir in the heavy cream, Parmesan cheese, and Italian seasoning, mixing until smooth.
Add the spinach to the sauce and let it wilt.
Return the salmon to the pan and let everything simmer together for 2-3 minutes.
Garnish with fresh basil, serve hot, and spoon extra sauce over the top.