Grease an 8x8-inch baking pan with butter or cooking spray, then line it with parchment paper and grease the parchment as well.
In a large mixing bowl, add the graham cracker crumbs, chocolate chips, vanilla, and sweetened condensed milk.
Mix well until all ingredients are combined. I used a Danish dough whisk. The batter will be thick. I would recommend a mixing spoon instead of a classic whisk as the batter will be all stuck in the middle.
Pour/scoop the mixture into the prepared pan.
Bake for 20 minutes until the brownies are golden brown and the edges are set.