If you want to cook all the pastries and do not want to freeze them, then you can use frozen spinach. To do so, thaw the spinach as per package instructions, squeeze out the excess liquid and then use following the method above. The frozen spinach I typically use is from the frozen aisle of Aldi and it is less than $1 for a 250g pack. I also used a separate brand from Woolworths (Bell farms brand) but it was prepared very fine, almost blended. There was heaps more liquid released and actually 2 packs (500g) of the Woolworths (Bell farms brand) ended up being a bit less than 1 cup. Unlike the Aldi brand which I got 1 cup worth of spinach from just 1 250g pack. You can use bunches of fresh spinach also but the time you need to prepare it will be increased due to the thorough cleanse of the soil you need to make.