If you want to add a bit of spice to this stir in 1 tbls. crushed red peppers to the spinach mixture.
The recipe calls for Panko which is an Asian style breadcrumbs. If you can’t find Panko you can substitute plain breadcrumbs instead.
You can prep this ahead of time. Store covered in the fridge and pop in the oven before serving, this may add a few minutes to the baking time depending on how cold it is.
If you must store leftover do so in an airtight container, and be sure you use it the next day. The longer it stays in the fridge the more watery it gets.