To make creamy ranch chicken with broccoli casserole, start by peeling and boiling the potatoes till they are tender.
WHILE THE POTATOES ARE COOKING START ON THE CHICKEN.Remove the tendon from the chicken tenderloin. To do that Grab the exposed end of the tendon, using a paper towel to get a better grip, and slip it between the tines of a fork. Then, pull up on the tendon while keeping the fork in place, thereby yanking it free from the meat. Chop the chicken tenderloins into small bite-sized cubes. Put a large pan on medium heat on the stove and let it heat up for a few minutes. Then add 2 tablespoons of olive oil and the chicken. Season the chicken with 2 tablespoons of dry ranch seasoning, and sautee the chicken for 5 minutes while stirring it on occasion so it has a chance to cook from all sides. Add 1 tablespoon of butter,3 cloves of minced garlic, and 1 chopped onion, and continue to saute for another 2 minutes. Transfer the chicken to a large bowl.
To the bowl add 1/2 cup sour cream, 1/3 cup mayonnaise, and freshly grated mozzarella cheese and sharp cheddar cheese (4 oz of each.)
Chop the broccoli into small pieces, then add 12oz of frozen broccoli florets (or you can use fresh broccoli florets). Mix all the ingredients together to make the cheesy broccoli casserole topping.
Once the potatoes are done cooking, drain the liquid then smash the potatoes till they are creamy with no lumps. I prefer to use a hand mixer to make them smooth, or you can use a potato masher. Then add 1/2 cup of whole milk, 1 egg yolk, 3 tablespoons of butter, and 1/4 cup of parmesan cheese. Mix it all together to form a creamy mashed potato.
To a casserole dish add the mashed potatoes, then evenly spread the ranch chicken with cheesy broccoli over the mashed potatoes. Sprinkle 1 cup of the panko bread crumbs ( or you can use crushed ritz crackers) all over the top.