Preheat the oven to 350°F. Butter six 3/4-cup silicone baking cups or oven-safe custard cups. Combine the figs (or dates) and boiling water, and set aside., To make the cake: Beat the 4 tablespoons (57g) butter, brown sugar, salt, and baking powder until fluffy., Beat in the egg, then the molasses and vanilla, then the flour., Purée the figs and water in a food processor or blender. Add the baking soda, and stir into the batter., Scoop into the prepared baking cups, placing a scant half cup batter in each. Place the molds on a baking sheet., Bake the cakes for 18 to 22 minutes, until a cake springs back when lightly pressed in the center. Remove from the oven, and cool in the molds or cups., To make the sauce: Cook the sugar, butter, and salt over medium heat until the mixture is a deep amber color; watch closely to prevent burning., Carefully mix in the cream. Cook the mixture until it's thick enough to coat a spoon., Unmold the cakes and serve with the sauce.