Prepare the frozen spinach as directed on the package. Place the prepared spinach in a strainer and push out the liquid. See Notes about fresh spinach
Slice the shallots and artichoke hearts; chop the garlic. Measure remaining ingredients.
Add 1 tablespoon of butter to a sauté pan over medium-high heat. When melted and starting to foam, add the shallots and sauté until starting to clear, about 2 minutes.
Add the artichoke hearts and garlic and sauté for another 2 minutes.
Add the Creole seasoning, kosher salt, ground black pepper, and cayenne pepper if using. Stir to mix thoroughly.
Add the remaining tablespoon of butter. As it melts, add the AP flour and stir well to combine with the vegetable mixture. Saute for about 2 to 3 minutes.
Add the heavy cream. Stir well while the cream begins to simmer. Lower the heat and maintain a simmer; continue stirring and shaking the pan until starting to thicken. This should take about 3 minutes.
Add the spinach and blend together. Stir in the Romano cheese.
Taste for salt and pepper and add if needed; continue to simmer until thickened to a creamy consistence.
Notes
Leftover spinach casserole can be refrigerated in an airtight container for 3 to 5 days. It can also be frozen for about 6 months. Thaw frozen leftovers in the fridge overnight. Reheat covered in a 350-degree oven for about 10 to 15 minutes or until warmed all the way through. This can also be reheated in the microwave or on the stovetop. Use frozen spinach steamable in a bag, although frozen spinach in a block also works. Fresh spinach will work. You would need 2 pounds of fresh as it reduces down. Make sure to drain any liquid in a colander or strainer then squeeze out the remaining water before using, regardless if it's frozen or fresh.