Heat the oven to 350°F. Generously grease a 12-cup fluted tube pan with shortening or cooking spray. If using shortening, use a paper towel or pastry brush to evenly spread it around the pan.

In a large 1-gallon plastic food storage bag, mix granulated sugar and cinnamon. Shake the bag up and down several times to mix well.

Separate the 2 cans of dough into 16 biscuits. Place biscuits on cutting board and cut each biscuit into quarters. Working with 8 to 10 biscuit pieces at a time, shake in the bag to thoroughly coat.

Arrange the coated biscuit pieces in the prepared pan. If using, sprinkle walnuts and raisins among the biscuit pieces as you arrange them. Melt butter, mix with brown sugar, pour over biscuit pieces, and bake for 30 to 40 minutes until golden brown.

Let cool for 5 minutes, then invert onto a serving plate.