1. Prepare the Pan:

1. Line an 8×8-inch square baking dish with parchment paper or lightly grease it. Set aside.

2. Cook the Maple Syrup Mixture:

1. In a heavy-bottomed saucepan, combine the maple syrup, heavy cream, butter, and salt.
2. Heat the mixture over medium heat, stirring occasionally, until the butter melts and the ingredients are fully combined.
3. Attach a candy thermometer to the side of the pan and continue to cook the mixture, without stirring, until it reaches soft-ball stage (238°F / 114°C). This can take about 15-20 minutes.

3. Cool the Mixture:

1. Remove the saucepan from the heat and allow the mixture to cool to about 110°F (43°C), without stirring. This can take about 15-20 minutes. The mixture should thicken slightly but remain pourable.

4. Beat the Fudge:

1. Using a wooden spoon or a hand mixer, beat the cooled mixture vigorously until it loses its glossy sheen and starts to thicken significantly, about 3-5 minutes. If using nuts, stir them in at this stage.

5. Pour and Set:

1. Quickly pour the fudge into the prepared pan, spreading it evenly with a spatula.
2. Let it cool completely at room temperature until firm, about 2 hours.

6. Slice and Serve:

1. Once set, lift the fudge out of the pan using the parchment paper. Cut it into small squares and serve.