Break the cookies into smaller pieces and place them in a coffee bean grinder or high-powered blender. Pulse the cookies until they are crushed into crumbs. Repeat as necessary.

In a small pot over low heat, combine the condensed milk, milk, and butter. Continuously stir the mixture as the butter melts, about 3 to 5 minutes.

Add vanilla extract and cinnamon. Mix well and simmer for 3 to 5 minutes.

In a large bowl, combine the butter mixture and cookie crumbs. Stir well.

Fold in the pureed pumpkin and mix until combined.