(1 sandwich cookie)
Preheat oven to 350°F. For the Cookies, beat butter, brown sugar and salt in large bowl with electric mixer on medium speed until light and fluffy. Add egg and maple flavor; mix well. Gradually beat in flour on low speed until well mixed. Roll out dough on generously floured surface to 1/4-inch thickness. Cut out with 1 1/2-inch round cookie cutter.
Bake 8 minutes or until cookies are lightly browned. Cool on baking sheets 1 minute. Remove to wire racks; cool completely.
For the Maple Creme Filling, beat butter and maple flavor in large bowl with electric mixer on medium speed until light and fluffy. Gradually add confectioners' sugar, beating until well blended after each addition and scraping sides and bottom of bowl frequently. Add water; beat until light and fluffy. Place about 1 teaspoon filling on the flat side of 1 cookie. Top with a second cookie, pressing gently to spread the filling. Repeat with remaining cookies and filling.