1. Preheat your oven to 375 F (190 C). Lightly grease a 10-12 cup Bundt pan with butter or non-stick spray.

2. Unroll the crescent roll dough from both cans. Separate the dough into individual triangles. Cut each triangle into 2-3 smaller pieces, creating bite-sized dough balls.

3. In a medium bowl, combine the granulated sugar and ground cinnamon. Toss the cut crescent dough pieces in this cinnamon-sugar mixture until they are thoroughly coated. Ensure every piece has a generous dusting.

4. Place the coated dough pieces evenly into the prepared Bundt pan. Don’t press them down; keep them relatively loose so the caramel sauce can seep through and they can expand during baking.

5. In a separate microwave-safe bowl, melt the unsalted butter. Stir in the sourdough starter, packed light brown sugar, vanilla extract, and a pinch of salt until well combined and smooth.

6. Carefully pour the sourdough caramel sauce evenly over the dough pieces in the Bundt pan. Make sure to distribute it over all the pieces. Place the Bundt pan on a baking sheet (to catch any potential drips) and bake for 25-30 minutes, or until the monkey bread is golden brown and bubbly. The center should be set, not overly jiggly.

7. Once baked, remove the pan from the oven and let it cool on a wire rack for 5-10 minutes. This cooling period is important as it allows the caramel to set slightly, preventing it from sticking too much.

8. Place a large serving plate upside down over the top of the Bundt pan. Carefully, but confidently, flip the pan and plate over together. The monkey bread should slide out onto the plate, with the gooey caramel sauce cascading over it. Serve immediately while warm, allowing everyone to pull off their own delicious pieces.