1 cup all-purpose flour
1/4 cup whole-wheat flour
1/4 cup granulated sugar
1/2 cup butter
1/2 cup firmly packed brown sugar
1/3 cup maple syrup
2 tbsp butter, melted
1 tsp vanilla
1 1/2 cups chopped walnuts
powdered sugar for garnish, if desired
Preheat oven to 375 degrees.
Spray a 9-inch square baking pan with nonstick cooking spray.
Mix the flours and granulated sugar together in a bowl. Cut in the butter until the mixture resembles coarse crumbs. Press mixture onto the bottom of the prepared baking pan. Bake at 375 for 15 minutes or just until lightly browned.
Beat the egg, brown sugar, syrup, melted butter, and vanilla together until well blended. Stir in the chopped walnuts. Spread evenly over the warm crust. Bake at 375 for 20 to 25 minutes or until the filling is firm around the edges but slightly soft in the center. Cool in the pan. Cut into 18 bars. Sprinkle with powdered sugar, if desired.