In the bowl of your stand mixer, add in heavy cream, vanilla extract and espresso powder. Use the whisk attachment and beat on high speed for about 1 minute. Pour in condensed milk. Beat on high until condensed milk is incorporated. Mixture should be thick.
Gently, fold in brownie chunks. Pour half of your mixture into a loaf pan or airtight container with a lid. Drizzle chocolate syrup or hot fudge over that layer. Add remaining mixture over the chocolate drizzle. Add one more layer of chocolate syrup on top. Run a chopstick or butterknife through the mixture, back and forth then side to side. This creates those beautiful chocolate swirls!
If using loaf pan, cover with plastic wrap. Refrigerate for at least 4 hours before enjoying.