Heat the Base: Combine heavy cream, agave nectar, and dark brown sugar in a glass measuring cup or small pot. Heat until scalding hot (steaming and starting to bubble around the edges, about 1 to 1.5 minutes in the microwave).

Layer & Soften: Place chocolate chips, cocoa powder, peanut butter, butter, and sea salt into the Vitamix container. Pour the scalding hot agave-cream mixture directly over the chocolate and let sit undisturbed for 60 seconds.

Blend to Emulsify: Secure the lid. Start the blender on Variable 1, quickly ramp up to Variable 8 or 10, and blend for 30 to 45 seconds until completely smooth and glossy.

Finish with Whiskey: Reduce speed to Variable 1. Remove the lid plug, pour in the peanut butter whiskey and vanilla extract, and blend on low for 10 seconds just until incorporated.