In large bowl, combine 1 cup butter, whipping cream and 1/2 teaspoon maple extract; blend well. Stir in flour until well mixed. Divide dough in half; shape each half into flattened disk. Wrap each in plastic wrap; refrigerate 1 hour for easier handling.
Heat oven to 375°F. On lightly floured surface, roll half of dough at a time to 1/8-inch thickness. Keep remaining half of dough refrigerated. Cut dough with 2-inch maple-leaf cookie cutter. Place 1 inch apart on ungreased cookies sheets. Sprinkle with sugar. With fork, prick each cookie 3 or 4 times.
Bake at 375°F. for 7 to 10 minutes or until slightly puffed and edges are light golden brown. Cool 1 minute; remove from cookie sheets. Cool 10 minutes or until completely cooled.
In small bowl, blend all filling ingredients, adding enough milk for desired spreading consistency; beat until smooth. Spread scant 1 teaspoon filling between 2 cooled cookies.