Butter an 8-inch square baking dish; line with parchment, allowing a 2-inch overhang on 2 sides. Butter lining (not overhang); set aside. Whisk flour, 1/4 teaspoon salt, and 1/4 cup nuts in a bowl.
Preheat oven to 350 degrees. Put 1/2 cup butter and 1/4 cup brown sugar into the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until pale and fluffy. Mix in flour mixture and 1 teaspoon maple syrup. Press dough evenly into bottom of prepared dish. Refrigerate 30 minutes. Bake until set in center and pale golden, 22 to 25 minutes. Transfer to a wire rack; let cool slightly.
Put remaining 6 tablespoons butter and 1/2 cup nuts into a small saucepan. Cook over medium-high heat, stirring constantly, until butter is very foamy and nuts are fragrant, 2 to 3 minutes. Add remaining 1/4 teaspoon salt, 3 tablespoons brown sugar, 1 teaspoon maple syrup, the ginger, maple sugar, corn syrup, and cream. Boil, stirring constantly, 2 minutes. Spread over crust. Let cool completely. Run a knife around non-parchment sides; lift out of dish by overhang. Cut into sixteen 2-inch squares.
Bars can be stored in an airtight container at room temperature up to 3 days.