Preheat oven to 375 degrees. Line 2 cookie sheets with parchment paper. In the bowl of an electric mixer, cream together the butter and brown sugar on medium high speed until fluffy and thoroughly combined. Add the eggs, one at a time, beating after each addition. Add the maple syrup, sour cream, and maple flavoring and beat until well combined.

In another mixing bowl, whisk together the flour, baking soda, powder, and salt. Gradually add the dry ingredients to the wet ingredients, beating on low speed. Increase speed and beat until thoroughly combined, about 1 additional minute.

Drop the dough by the rounded Tablespoon onto the cookie sheets, leaving about an inch and a half between cookies. Bake for 10-12 minutes or until cookies are puffed and lightly browned.

Combine the brown sugar and cream in a small sauce pan. Bring the mixture to a boil over medium heat, whisking constantly. Boil for 4 minutes. Remove the mixture from heat and stir in the butter and maple extract. Add 1 1/4 cups powdered sugar and whisk until smooth. If needed add an additional 1/4 cup of powdered sugar. You want the frosting to be thick but still spreadable. Immediately spread the frosting on the cookies. Sprinkle with chopped pecans.

Allow the cookies to set, then store in an airtight container. Cookies will stay fresh for 3-4 days, but pecans will lose their crunch after 2 days.