Step 1: Preheat your oven to 300°F (150°C). Line a baking sheet with parchment paper.
Step 2: In a food processor, pulse the butter cookies until fine crumbs form. Be careful not to over-process into a paste.
Step 3: In a medium bowl, combine the cookie crumbs, melted unsalted butter, and light brown sugar. Mix until the crumbs are evenly moistened.
Step 4: Spread the mixture evenly in a single layer on the prepared baking sheet.
Step 5: Bake for 10-12 minutes, stirring gently halfway through, until the crumbs are fragrant and lightly golden brown. Be careful not to burn them.
Step 6: Remove from oven and let cool completely on the baking sheet. As they cool, they will become delightfully crunchy.
Step 7: Take your vanilla ice cream out of the freezer and let it soften for about 10-15 minutes at room temperature.
Step 8: Choose your serving dishes (tall sundae glasses work best).
Step 9: Start with a generous scoop of softened vanilla ice cream at the bottom of each glass.
Step 10: Drizzle a generous amount of chocolate fudge syrup over the ice cream.
Step 11: Sprinkle a good layer of your homemade cookie crunch over the chocolate syrup.
Step 12: Repeat the layers: another scoop of ice cream, more chocolate syrup, and a final, bountiful sprinkle of cookie crunch on top.
Step 13: Serve immediately and enjoy!