In a small bowl, combine the diced chicken breasts or tenders with garlic powder, salt, black pepper, and crushed red pepper flakes. Toss everything well to evenly coat the chicken pieces with the seasonings. This helps the chicken absorb flavor before cooking.
Heat 1 tablespoon of olive oil in a large high-sided pan over medium-high heat. Add the marinated chicken from Step 1 and cook for 10-12 minutes, turning occasionally, until the chicken is browned on all sides and cooked through. Remove the chicken from the pan and set aside. In the same pan (no need to clean), add the remaining tablespoon of olive oil. Toss in the asparagus pieces and sauté for about 2 minutes until they are tender but still crisp. Remove the asparagus and set it aside with the cooked chicken.
In the same pan, add the chopped onion and sauté for about 3 minutes until it softens. Add the orzo pasta and finely chopped garlic, then cook, stirring frequently, until the orzo begins to toast slightly and gives off a nutty aroma, about 3 more minutes. I like to give the orzo a light golden color here for extra flavor.
Pour the chicken broth into the pan and bring to a simmer, ensuring to scrape the bottom of the pan to incorporate any browned bits. Cover the pan with a lid and cook for about 7 minutes, stirring halfway through, until most of the liquid is absorbed by the orzo. (Tip: You can microwave your broth before adding it to the pan to speed up the cooking time.)
Uncover the pan and stir in the cooked chicken, sautéed asparagus, half-and-half or milk, grated parmesan cheese, baby spinach, and thyme. Cook for 1 to 2 more minutes, stirring gently, until the spinach is wilted, the cheese is melted, and all ingredients are heated through.
Serve the orzo mixture immediately, garnished with chopped parsley and extra grated parmesan cheese. I always add an extra sprinkle of parmesan on top for even more cheesy goodness.