Bring a large pot of salted water to a rapid boil. Add uncooked pasta and cook according to package instructions until al dente, usually about 8-10 minutes. Reserve about 1 cup of the pasta water, then drain and set aside.

In a large skillet over medium heat, melt butter until bubbly. Add minced garlic and stir for about 30 seconds.

Gradually sprinkle in flour, whisking constantly for 30 seconds. Pour in white wine or broth, Dijon mustard, lemon juice, and Italian seasoning. Reduce mixture by half, about 3-5 minutes.

Stir in sun-dried tomatoes and heavy cream. Simmer for about 5 minutes until thickened.

Stir in Parmesan cheese until melted and add fresh spinach. Cook for 1-2 minutes until wilted.

Toss cooked pasta into the skillet with the sauce. Mix well, adding reserved pasta water if needed, and season with salt and pepper to taste. Serve warm.