In a large pot or Dutch oven, heat the olive oil and butter over medium heat. Once melted, add the chopped onion and sauté until translucent, about 3-4 minutes. Stir in the minced garlic and cook for an additional minute until fragrant.
Next, stir in the sun-dried tomatoes and Cajun seasoning. Cook for another 2 minutes, allowing the flavors to meld together.
Add the uncooked orzo pasta to the pot, stirring well to coat it with the buttery mixture. Toasting the orzo for a minute will enhance its flavor.
Carefully add the low sodium chicken broth and bring the mixture to a gentle boil. Reduce the heat to low, cover, and let it simmer for about 10-12 minutes, or until the orzo is tender and has absorbed most of the liquid.
Once the orzo is cooked, stir in the heavy cream, shredded chicken, and lemon juice. Mix well until everything is combined and creamy. Allow it to heat through for about 2-3 minutes.
Finally, remove the pot from heat and stir in the freshly grated Parmesan cheese until melted and creamy. Serve hot, garnished with additional cheese or parsley if desired.