Preheat your oven to 350°F (175°C) and line a large-rimmed baking sheet with parchment paper. Spread the mini peanut butter sandwich crackers in a single, even layer on the sheet.
In a medium saucepan over medium-high heat, combine the butter, 1/3 cup plus 2 tablespoons dark brown sugar, vanilla extract, and 1/2 teaspoon cinnamon. Stir constantly until the mixture is completely combined and begins to simmer, about 2-4 minutes. Remove from heat.
Carefully pour the butter mixture over the crackers. Using a silicone spatula, gently toss to coat the crackers evenly.
Bake for 10 minutes, flipping and tossing the crackers halfway through. You’ll know they’re ready when the mixture is bubbling and the crackers take on a golden-brown hue.
While the crackers are baking, mix the granulated sugar with the remaining 3/4 teaspoon cinnamon in a small bowl.
Remove the crackers from the oven and let them cool slightly, about 1-2 minutes. Transfer them to a large bowl and toss them with the cinnamon sugar until fully coated.
Place the churro bites in a serving dish and enjoy while warm, or let them cool completely for an equally delightful treat.