Combine brown sugar, cream, butter, and salt in a large heavy saucepan. Don?t skimp on the size of the pan. Stir to integrate. Apply medium heat, stirring constantly, until the mixture comes to a healthy boil.Reduce heat to low, and simmer at a slight boil for 15 minutes, stirring every few minutes to eliminate any boil-inhibiting skin which might form. Add the baking soda, remove from the heat, and mix it in well. Next stir in the vanilla and confectioner?s sugar. Keep mixing until the sugar is well-incorporated. Then, and not a moment before, add the reserved brown sugar.Pour into a square or rectangular pan such as an 8?8 or 9?9 inch, lined with parchment paper. Let cool to room temperature (a couple hours at least, more depending on weather). Cut into inch-square pieces, or less.Serving Size: makes about 64 squaresNumber of Servings: 64Recipe submitted by SparkPeople user 14KRISTEN.