01 -
Line an 8-inch square pan with parchment paper, leaving overhang on two sides. Lightly butter the parchment or mist it with nonstick spray.
02 -
Add the sugar, evaporated milk, butter, maple syrup, and salt to a heavy medium saucepan. Cook over medium heat, stirring constantly, until the mixture reaches a full rolling boil.
03 -
Keep boiling and stirring until a candy thermometer reads 234°F to 236°F, about 4-6 minutes after the full boil starts. Remove the pan from the heat right away.
04 -
Add the white chocolate chips, marshmallow creme, maple extract, and vanilla. Stir firmly until the chips are melted and the mixture looks smooth and glossy.
05 -
Fold in the chopped walnuts. Scrape the fudge into the prepared pan and smooth the top quickly with a spatula.
06 -
Press walnut pieces on top if using and sprinkle with a little flaky salt if desired. Refrigerate until firm, 1-2 hours, then lift out and cut into 36 squares.