Preheat and grease pan: Preheat the oven to 350°F. Grease a 10-inch bundt pan thoroughly, getting into every ridge so the bread releases cleanly later.
Cut the biscuit dough: Open the cans of biscuit dough and cut each biscuit into quarters. You should end up with small, bite-sized pieces of dough.
Mix cinnamon sugar: In a large zip-top bag, combine the granulated sugar and ground cinnamon. Shake to mix evenly.
Coat the dough pieces: Add the cut dough pieces to the bag in batches and shake until each piece is fully coated in cinnamon sugar.
Layer dough in the pan: Scatter the coated dough pieces into the prepared pan in loose, uneven layers. Sprinkle chopped pecans between layers if using.
Make the caramel sauce: In a small saucepan, melt the butter with the brown sugar, vanilla extract, and salt over medium heat, stirring until smooth, about 3 minutes.
Pour caramel over dough: Pour the warm caramel sauce evenly over the layered dough pieces, letting it seep down into the gaps.
Bake until golden: Bake for 30 to 35 minutes, until the top is deep golden brown and a piece from the center pulls apart without looking doughy inside.
Rest before inverting: Remove the pan from the oven and let it rest for 5 minutes. This lets the caramel settle before flipping.
Invert and serve: Place a serving plate over the pan and carefully flip it over so the bread releases, caramel side up. Serve warm, pulling pieces apart by hand.