Line the 8-inch square baking dish with parchment paper, leaving some overhang for easy removal of the fudge later.
In a medium saucepan, combine maple syrup, heavy cream, granulated sugar, butter, and salt.
Place the saucepan over medium heat and stir continuously until the mixture comes to a gentle boil.
Attach a candy thermometer to the saucepan and continue to cook, stirring frequently, until the temperature reaches 240°F (soft-ball stage).
Remove the saucepan from the heat and let it sit for about 5 minutes to cool slightly without stirring.
Add vanilla extract and toasted pecans to the warm mixture, stirring until well combined.
Pour the fudge mixture into the prepared baking dish and spread it evenly using a spatula.
Let the fudge cool at room temperature for about 2 hours until set.
Once set, lift the fudge out of the dish using the parchment paper overhang and cut it into 16 pieces.