This sounds easy enough if you remember to plan ahead far enough to make the ice cubes out of coffee.  I always have coffee on hand,but right now I don't have a blender.  Wonder if a handheld  blender would work out all right?  

Also, I would not use stevia.  Not the same composition as sugar, necessary for the texture.  I used to use stevia for everything when I was on fat flush but I don't do that anymore.  Pretty soon everything you eat will start tasting like it!  If you use REAL stevia, not one of the fake imposter types, it might be ok, but I would just use sugar or even brown sugar.

https://www.thriftyfrugalmom.com/recipe-easy-homemade-caramel-frappe/#recipe