Heat olive oil in a large pot or Dutch oven over medium-high heat. Season your chicken pieces with salt and pepper, then sear them for 3-4 minutes per side until golden brown. Remove the chicken and set it aside on a clean plate.
In the same pot, sauté your diced onion for 2-3 minutes until softened and fragrant. Add minced garlic and cook for another 30 seconds, stirring constantly to prevent burning and to release those wonderful aromatic flavors.
Add the long grain white rice to the pot and stir for about 1 minute, coating it with the oil and aromatics. Pour in the chicken broth, add the bay leaf, thyme, and rosemary, then return the seared chicken pieces to the pot.
Bring everything to a boil, then reduce heat to low and cover with a lid for 15-18 minutes. The rice and chicken cook together, creating a one-pot creamy hearty chicken and rice that's both convenient and delicious.
After the rice has absorbed most of the liquid, stir in the heavy cream, frozen mixed vegetables, butter, and parmesan cheese. Cook uncovered for 2-3 minutes until heated through, then taste and adjust seasoning as needed before serving.