Caramel Sauce Ingredients:
Preheat your oven to 350 degrees F.
Grease a 9-inch pan.
Beat the brown sugar and butter together in with a mixer (or by hand) until smooth.
Mix in the molasses, eggs, sourdough starter, and baking soda.
In a separate bowl, combine the flour, ginger, cinnamon, and salt.
Add the dry ingredients to the wet mixture, stir, then mix in the hot water until just combined.
Spoon the batter into the prepared pan, then bake for 40-45 minutes, or until a toothpick inserted into the middle comes out clean.
Serve warm, with caramel sauce drizzled over the top.
To Make the Caramel Sauce:
In a small saucepan over medium heat, whisk together the sugar and cornstarch, then stir in 1?4 cup water and whisk until smooth. Add the cream and butter and cook until the sauce is thickened and bubbly. Remove the pan from the heat and stir in the vanilla. Serve immediately or store in an airtight container in the fridge for up to 3 days. To reheat, warm in a small saucepan over medium heat until heated through.