For the filling, combine all of the filling ingredients in a high-speed blender or food processor, and blend until thoroughly combined. You may need to stop and scrape down the sides, or use a tamper, to keep everything blending smoothly. You can adjust the sweetness to taste, if necessary.
Remove the crust from the freezer, and pour in the filling, using a spatula to smooth the top. Drizzle an additional ½ cup of melted dark chocolate chips over the top, if desired.
Return the bars to the freezer, and allow them to set for at least 6 hours, or overnight, before cutting and serving.