In a heavy-bottomed, 2 qt pot over medium heat, melt the butter until it's gently boiling.
Whisk in the brown sugar, pumpkin spice and flavorings.
Boil the mixture for 5-6 minutes or until it has the appearance of maple syrup.
Remove the pot from the stove and, carefully, whisk in the warmed cream. The mixture will bubble and steam, so take care not to burn yourself. Whisk constantly until the mixture is smooth and free of clumps.
Remove from heat and allow to cool. Once cool enough to handle, serve as desired; or bottle in a glass jar with a tight-fitting lid. The toffee sauce will thicken under refrigeration, but only needs to be warmed in the microwave when ready to use. This will keep for two weeks in the fridge.