Heat the olive oil in a 12-inch deep skillet over medium-high heat. Add the Italian sausage and cook for 5–7 minutes, breaking it into small pieces with a wooden spoon, until browned and cooked through. Transfer the sausage to a plate, leaving the flavorful drippings in the skillet.

Reduce the heat to medium: Add the diced onion to the skillet and cook for 3–4 minutes, stirring occasionally, until softened and translucent. Add the garlic and cook for 30 seconds, just until fragrant.

Stir in the dry orzo and cook for 1–2 minutes, stirring frequently. The pasta should become lightly glossy and smell slightly nutty, but it should not brown deeply.

Add the diced tomatoes with their juices, chicken broth, Italian seasoning, kosher salt, and black pepper. Stir well, scraping the bottom of the skillet to loosen any browned bits.

Bring the mixture to a gentle boil, then reduce the heat to medium-low. Simmer uncovered for 10–12 minutes, stirring every few minutes so the orzo does not settle and stick to the bottom.

The orzo should be tender with a creamy, slightly loose sauce. If the liquid is disappearing before the pasta is tender, add 1/4 cup (60 mL) of additional broth at a time and continue simmering. If the orzo is tender but the sauce is too loose, simmer for another 1–2 minutes.

Stir the browned sausage back into the skillet and cook for 1–2 minutes to heat it through.

Reduce the heat to low: Stir in the heavy cream and Parmesan until the cheese melts and the sauce becomes creamy. Do not bring the cream to a hard boil.

Stir in the baby spinach and cook for 1–2 minutes, just until wilted and evenly distributed. The mixture should remain creamy rather than dry.

Remove the skillet from the heat and stir in the lemon juice. Taste and adjust the seasoning if needed. Let the sausage orzo rest for 5 minutes; the sauce will thicken slightly as it stands.

Sprinkle with the optional fresh parsley and serve warm. If the orzo becomes thicker than desired while sitting, loosen it with a small splash of warm broth.