• Set the oven to 350?
• Lightly butter a 9x9 round or square or baking dish.
• Cream the softened butter and sugar together until well combined. Make sure there are no big lumps of brown sugar left. Beat in the maple extract.
• With the mixer on low mix in the flours and cornstarch Note: remember you are adding 1 cup plus 2 tablespoons of flour. Then fold the nuts. Blend until everything is evenly combined and there is no dry flour left. I like to finish mixing by hand to make sure everything is well incorporated.
• Drop the dough in clumps, evenly across the bottom of your prepared pan.
• Pat the dough down with floured hands, nudging it out so it fills the pan and covers the whole bottom evenly. You don't want a mound of dough in the middle, you want to flatten it out from side to side, evenly. I like to use an offset spatula to smooth the surface of the dough. If you like you can press a few extra walnut pieces into the top of the dough for a pretty look. Note: to smooth out the surface of your dough place a piece of parchment or waxed paper over the surface and smooth it out with your hands. Remove and discard the paper before baking.
• Bake for about 30 minutes. The top will still look pale, but the dough will be just beginning to turn golden around the edges. Let the shortbread cool in the pan for at least 20 minutes before attempting to slice. It will be quite crumbly, so the longer you let it cool the easier it will be to slice.

optional glaze

• Stir the sugar, maple syrup, and maple extract together until smooth. Thin down with water to the desired consistency.
• Drizzle the glaze over the cooled shortbread and top with a sprinkle of chopped walnuts, if desired.