Preheat oven to 350 degrees F.

For the cookie: In a medium mixing bowl, sift together the flour, salt, and cinnamon. In a large mixing bowl, with an electric mixer, cream the butter, granulated sugar, and dark brown sugar. Beat in egg whites, vanilla and butter flavor extracts. Carefully fold in the flour mixture with a rubber spatula. Wrap dough in plastic and chill until dough is firm, about 30 minutes in freezer.

For the peach filling: In a medium mixing bowl, mix peach preserves with cinnamon, nutmeg, lemon zest and lemon extract. When dough has chilled, roll out dough 1/4-inch thick and cut into pieces about 2 1/2 inches wide and 3 inches long. Place a teaspoon of peach filling in the center of each piece and fold each end of the dough to the center to cover the filling. Flatten cookies slightly and place them seam down and 1-inch apart on a parchment-lined cookie sheet. Bake for about 12 minutes, until lightly browned and just firm. Cool on the cookie sheet. Dust cookies with a mixture of powdered sugar and cinnamon, if using.