Heat a large, deep skillet over medium heat. Add the Italian sausage and cook for about 4–5 minutes, breaking it apart with a wooden spoon as it cooks.
Add the chopped onion and continue cooking for another 4–5 minutes, until the sausage is browned and the onion has softened.
If there is a large amount of rendered fat in the skillet, carefully drain some, leaving about 1 tablespoon behind for flavor.
Stir in the sun-dried tomatoes and garlic. Cook for 1–2 minutes, until the garlic is fragrant.
Add the uncooked orzo and stir well, allowing it to toast with the sausage mixture for about 1 minute.
Pour in the chicken broth and heavy cream. Stir to combine and bring the mixture to a gentle simmer.
Reduce the heat to medium-low and cook for about 9–12 minutes, stirring frequently to prevent the orzo from sticking to the bottom of the skillet.
The orzo should be tender and creamy, with most of the liquid absorbed.
Remove the skillet from the heat.
Stir in the spinach and Parmesan cheese. Continue stirring until the spinach wilts and the Parmesan melts into the sauce.
Taste and season with freshly ground black pepper and additional salt, if needed. Keep in mind that the sausage, broth, sun-dried tomatoes, and Parmesan can all be salty, so taste before adding more salt.
If the orzo seems too thick, stir in a splash of warm chicken broth or cream until it reaches your desired consistency.
Serve immediately and enjoy!