Preheat the oven to 380 to 400, depending on how hot your oven is.
Cream the butter and sugar until smooth. Add eggs, one at a time. In a small bowl, mix together flour, baking powder, and baking soda. Add dry ingredients to wet ones in batches, alternating with sour cream. Drop by Tablespoon fulls onto a lightly greased baking sheet. Bake for 7-9 minutes. cool completely.
For icing glaze:.
Mix powdered sugar, maple syrup, and vanilla extract in a bowl, if the glaze is too thick add more maple or some milk/water. transfer to a flat shallow dish (like a pie pan). spread glaze on cookies, and quickly top with crushed walnuts.
( Icing takes about an hour to harden, their less messy and taste better when the glaze is cool and hardened.).