Combine butter, sweetener, and 4 tablespoons of the cream over medium heat. Stir until sweetener is dissolved. Cook until it is a deep golden brown. As soon as it reached that deep color (right before burning) remove from the heat and immediately add the other 2 tablespoons of heavy cream, maple extract, and salt. Stir until smooth.
Pour into silicone candy molds. These will solidify in the refrigerator. It might take a couple DAYS. Once they are firm you can pop them out of the mold.