Preheat your oven to 325°F (160°C) and line a baking sheet with parchment paper.

Crush about 10–12 graham crackers in a medium bowl until you have a mix of fine crumbs and chunkier pieces. Add in ¼ cup of granulated sugar, a pinch of salt, and ½ teaspoon of ground cinnamon (if using). Stir until evenly combined.

Add ½ cup of melted unsalted butter and 1 teaspoon of vanilla extract to the dry mixture. Stir briskly until well coated.

Pour the mixture onto the baking sheet, spreading it out evenly. Bake for 8-12 minutes, checking starting at 8 minutes until golden brown.

Let the crumble cool at room temperature for about 10-15 minutes before breaking it into pieces and storing in an airtight container.