• Preheat the oven to 350˚F. In a 9 by 13 inch oven-safe baking pan, combine rice, 1 cup chicken stock, butter, ½ teaspoon Italian seasoning and a pinch of salt and pepper. Cover tightly with foil and bake for 30 minutes.
• Meanwhile, season the chicken with salt, pepper, paprika and remaining Italian seasoning. Add oil to a medium skillet over medium-high heat. Once the oil is shimmering, add chicken and cook for about 5 minutes, flipping halfway through, or until golden brown all over, but not yet cooked through. Remove from pan and cut into small cubes.
• To the same skillet, add onion and cook for 5 minutes. Season with salt and pepper. Add mushrooms and cook for 10 minutes, until they are no longer giving off moisture. Add garlic and cook for 1 more minute, until fragrant.
• Add remaining 2-3 cups chicken stock and sour cream and bring to a gentle simmer. Once it reaches a simmer, stir in the reserved chicken and remove from heat.
• Once rice is done cooking in the oven, uncover and pour the creamy mushroom and chicken mixture on top. Cover again and return to the oven for 15 minute, until the chicken is cooked through and the casserole sauce is thickened. Serve warm.

To Freeze Casserole

• If you wish to make this casserole ahead, instead of baking right away, let the casserole cool to room temperature then cover tightly with a layer of foil and plastic wrap and freeze. When ready to serve, let the frozen casserole defrost overnight in the fridge. Remove and discard the plastic wrap and bake (covered) in a 350˚F oven for about 30 minutes, or until heated through.