Preheat oven to 350°F. Toast pecans on a rimmed baking sheet, tossing once, until fragrant and slightly darkened, 10–15 minutes. Let cool, then coarsely chop.
Meanwhile, butter loaf pan. Attach candy thermometer to a large heavy-bottomed pot or Dutch oven set over medium heat. Cook maple syrup, cream, and salt, whisking constantly, and bring to a boil. Stop whisking and continue to boil until thermometer registers 238°F, about 40 minutes. Immediately remove from heat and let cool to 130°F, about 40 minutes.
Transfer to a stand mixer fitted with the paddle attachment (or use an electric mixer or wooden spoon) and beat on medium speed until fudge is stiff and opaque, about 12 minutes. Fold in pecans. Scrape fudge into prepared pan; smooth surface. Chill until cool and firm, about 2 hours.
Fudge can be made 1 week ahead; tightly wrap and chill.
Source from: https://www.epicurious.com/recipes/food/views/maple-pecan-fudge