Preheat oven to 350 degrees. Spray a shallow baking dish with non-stick spray.
Remove the excess water from the thawed spinach. (I use a clean towel and squeeze the water out of the spinach.)
In a medium bowl, add the spinach, cream cheese, sour cream, ranch seasoning, garlic, cayenne pepper (if using), and 1/2 cup of the cheese. Stir to fully combine.
Pour the mixture and evenly spread into the prepared baking dish.
Bake for 20 minutes.
Remove from the oven, and sprinkle the remaining 1/2 cup cheese over the top.
Place back in the oven for 5 minutes or until the cheese on top has melted.
Serve warm with tortilla chips.
Enjoy!