Preheat oven to 375º.
Mix thoroughly the butter, cream and flour. Cover and chill.
Roll about 1/3 of dough at a time to 1/8" thick on floured
surface, as in pie crust. Keep remaining dough chilled. Cut
into 1-1/2: rounds. Sprinkle sugar on tops of each round.
Turn rounds over and sprinkle the other side. Place on
cookie sheet with parchment paper and prick round with fork
four times across each top. Bake 7 - 9 minutes until set, but
not brown. Cool before putting together with cream filling.
Cream butter, powdered sugar, and vanilla until smooth and
fluffy. Tint with a few drops of food coloring, depending on the
season (pink for spring, green Christmas, etc). Add a few
drops of milk or water, if necessary, for spreadability.