Preheat your oven to 350°F (175°C) and line a rimmed baking sheet with parchment paper. Arrange saltine crackers in a single layer.

Combine unsalted butter and brown sugar in a medium saucepan. Heat over medium, stirring constantly until bubbling, then boil for 3 minutes.

Remove from heat and stir in vanilla extract. Carefully pour the hot toffee mixture over the saltine crackers and spread it evenly.

Bake in the preheated oven for 5-6 minutes until bubbling and crackers have absorbed the caramel.

Sprinkle a mixture of cinnamon and granulated sugar over the hot toffee immediately after removing from oven.

Allow to cool at room temperature for about 10 minutes, then transfer to the refrigerator for 1-2 hours until set.

Once set, break into squares or cut for uniform pieces. Drizzle with optional frosting if desired before serving.