Hortopita is like spanakopita's cousin! It's made with greens and you can pretty much use any type of greens that are in season. If you are in the United States, it is pretty easy to find collard greens but if you are in Greece you might be able to get a wider variety. One of the most important tips that I can give you about making hortopita is washing the greens very very well to get any dirt out. Sometimes hortopita can have a gritty or earthy flavor that's not so appealing.