Nutrition per serving may change if servings are adjusted.
1 cup pure maple syrup, preferably dark amber
1 cup packed light brown sugar
1/2 cup granulated sugar
1 cup chopped walnuts
Line two baking sheets with wax paper or aluminum foil. Combine maple syrup, brown sugar and granulated sugar in a heavy medium saucepan; heat over medium heat, stirring occasionally, until the sugar has dissolved. Clip a candy thermometer to the pan and cook, without stirring, until the syrup reaches 250 °F and is at hard-ball stage (when a bit of syrup dropped into ice water forms a hard ball). This will take 5 to 7 minutes. Remove from the heat and stir in walnuts.
Working quickly, drop the mixture by heaping tablespoonfuls onto the prepared baking sheets. (If the mixture hardens, return the pan to low heat and stir until smooth.) Let the pralines stand, uncovered, at room temperature until firm, about 30 minutes. Carefully lift the pralines from the wax paper or foil.
Make Ahead Tip: Store in an airtight container, with wax paper between each layer, in a cool, dry place for up to 1 week.