Aji verde sauce: combine all ingredients in a blender and blend until the sauce is smooth.
Transfer to a sealed container and store in the refrigerator for no more than 2 weeks.
Chicken and rice: add a tablespoon of butter to a large pot over medium heat. When the butter is melted, add diced onion and cook for 5 to 6 minutes or until the onion starts to soften.
Remove all of the onion to a large bowl and add a teaspoon of butter to the pot. Add in just enough chicken pieces to cover the bottom of the pot but try not to crowd the pieces too close to each other. Cook for 3 minutes, flip each chicken piece, and cook for an additional 2 minutes, then remove the chicken pieces to the bowl with the onion. Cook the chicken in batches with a teaspoon of butter each time until all of the chicken pieces have cooked for about 5 minutes. The chicken will not be fully cooked at this point, but it should have gotten a little bit of browning on the exterior.
Once all the chicken has been cooked a little and then moved to the bowl, add stock, Better Than Bullion, salt, pepper, MSG, and everything from the bowl with the onion and chicken in it, including any residual juices. Add the rice, stir everything in the pot together, and bring to a boil.
Once boiling, reduce heat to low, cover the pot, and simmer for 20 minutes.
After 20 minutes, uncover the pot, add the heavy cream and Parmesan cheese, and stir everything together. Add parsley if desired and stir. Store in a sealed container in the refrigerator until time to sandwich.
Sandwich assembly: warm a naan by toasting in the oven or in a pan until it's a bit more pliable.
Warm the chicken and rice in a bowl in the microwave with a teaspoon of cream, broth, or water added. You can also do this in a small pot with just a bit of liquid added to make sure things stay moist.
The naan is going to be folded on top of itself, so you only want to put fillings on one side of the circle. Add half of the cheese to the naan and then top that with the warmed chicken and rice. Sprinkle on some chopped cilantro seeds and drizzle on a bit of the aji verde sauce.
Top the sauce with the second portion of cheese and then fold the naan over to sandwich the ingredients.
Panini: add a tiny bit of oil to the outside of the naan and place it in a panini press. If you do not have a panini press, you can use a hot cast-iron skillet with another skillet on top of the folded-over naan, pressing it down. This will grill the bottom side, and you will have to flip the sandwich, but it will work just fine.
Once the naan has browned on the exterior and the fillings seem warmed through, the sandwich is complete. Serve and enjoy.