FILLING: Place all of the ingredients into a blender and puree until totally smooth. Transfer to a saucepan, place over medium-high heat, and whisk continuously until the mixture has thickened, about 5 minutes. It goes from not-thick to THICK really fast, so keep whisking until the mixture is noticeably thicker. Once thick, pour the filling into the cooled pie crust and let set, at least 15 minutes.