Prep:

1. Prepare all the ingredients: Chop the onion, celery, carrots, garlic, and mushrooms as indicated in the ‘Ingredients’ section. Clean and pat-dry the chicken breasts with paper towels. Squeeze the lemon and set aside the juice in a small bottle or bowl (if using). Measure out the cream, milk, rice, and water, and set aside. Combine all the spices in a small bowl – the kosher salt, freshly cracked black pepper, ground cayenne, crushed red pepper chili flakes, onion powder, garlic powder, dried thyme, dried dill, and oregano flakes. Cover and set aside.

For the Chicken:

1. Preheat oven to 175°C/350°F. Line a baking tray with a sheet of aluminum foil and brush lightly with olive oil (or any other cooking oil you prefer).
2. In a large bowl, add the kosher salt, freshly cracked black pepper, paprika, and garlic powder. Mix with a spoon or use a small whisk to combine the spices and seasonings until fully integrated.
3. Brush olive oil on the chicken breasts then dip them into the bowl and rub with the seasonings and spices until they are fully coated. (The oil helps to keep the chicken juicy during baking and allows the seasonings to better stick to the chicken breasts.)
4. Place the chicken breasts (plump side up) on the foil lined baking tray and bake for 19-21 minutes, turning once using tongs halfway through.
5. Remove the baking tray from the oven and let the chicken rest for 10-12 minutes to lock in all the juices. Transfer the chicken breasts to a chopping board, making sure to let any extra liquid/juices drip onto the foil before placing them on the board. Cut into bite sized pieces with a sharp knife and set aside. (Note: The chicken can be cooked 1-3 days in advance. If making the chicken ahead, store in an airtight container in the refrigerator.)

For the Creamy Chicken Mushroom Rice Soup:

1. Cook the mushrooms: In a large cast iron skillet (or a large Dutch oven), heat ½ tablespoon extra virgin olive oil over medium- high heat. Once hot, add a fourth of the mushrooms and cook undisturbed for 1-2 minutes. Then turn them over and cook the other side for another 1-2 minutes until evenly browned and slightly crisp. Transfer to a clean bowl and repeat thrice with the remainder sliced mushrooms, adding another ½ tablespoon of extra virgin oil after cooking the second batch. (Note: Do not overcrowd the pan as it will cause the mushrooms to release water and steam instead of brown and crisp up. You want them to brown so that they are more flavorful in the soup.) 
2. Sauté veggies and aromatics: Heat the unsalted butter and remainder 1 tablespoon of extra virgin olive oil in a large Dutch oven or stockpot over medium-high heat. Once hot, add the onions, carrots, and celery and sauté for 4-5 minutes until softened. Then add the garlic and sauté for another 1-2 minutes or until fragrant.
3. Add flour and liquids: Add the all-purpose flour and mix to combine with the veggies. Cook for 1-2 minutes to get rid of the floury taste, then lower the heat and slowly pour in the chicken broth, milk, cooking cream, and water while continuing to stir. 
4. Add spices and seasonings: Stir in all of the spices and seasonings in the bowl you made earlier until combined. Then cover and allow the soup to simmer for 10-15 minutes, or until it thickens.
5. Cook rice and add everything else: Uncover the pot and add the uncooked rice. Cook, stirring periodically for 10 minutes or until the rice has fully cooked through. Then lower the heat to low and add the chicken and freshly squeezed lemon juice (if using). Stir continuously for 3-4 minutes (to prevent curdling), or until the chicken has fully heated through.
   To Serve: Ladle the soup into individual bowls and garnish with some chopped fresh parsley or fresh coriander, freshly cracked black pepper, and a drizzle of extra virgin olive oil if desired. Feel free to add any of your favorite toppings like freshly grated cheese, cooked bacon pieces, etc.