To create the filling, most of the steps can be done one-at-a-time in a food processor. I find it works best to chop each ingredient on its own (no need to wash the processor in between), and then combine everything into a large bowl and mix by hand. A blender will work too, or in a pinch you can always use a knife and lots of chopping. I prefer to use the
mini-chopper attachment that came with our immersion blender (affiliate link), which is much easier to clean than our big food processor.