Most recipes use pistachio instant pudding mix to make the muffins green and give them their pistachio flavor. This is the easiest of easy muffin recipes as it only uses staple pantry ingredients with a few possible variations, without the need for any premade or instant pistachio pudding mix or cake mix. The muffins will naturally be light green because of the pistachios, however, for a greener end result, you can add a little food coloring.