Preheat oven to 350 degrees F. Lightly grease a 16 cup muffin pan.
Open biscuits and pull them apart. Cut each individual biscuit into 8 pieces.
Pour the granulated sugar and cinnamon into a large resealable bag or dish. Mix well, then add the biscuit dough and toss in the cinnamon sugar until coated.
Place the dark brown sugar and the butter in a microwave-safe dish and then microwave for 30 seconds. Stop and stir, and microwave for 15 seconds at a time until the butter is melted.
Add approximately 2 teaspoons of the butter and brown sugar mixture to each muffin cup.
Place 8 pieces of dough in each muffin cup.
Spoon the remaining butter and brown sugar mixture over each set of dough.
Bake for 20 minutes.
Remove from oven and let cool for 2-3 minutes before turning them out of the pan.
Enjoy warm or let cool completely before storing for later.