In a medium bowl mix together flour, powder, nutmeg, and salt. Set aside. In a large mixing bowl, cream butter and sugar together. Add eggs and vanilla. Add half of the flour mixture. While mixing on low speed, slowly pour in the cream. Add remaining flour and mix until combined. The dough will be very soft and sticky. Wrap dough in plastic wrap and chill overnight.
On a floured surface roll out dough with a rolling pin to about 1/4" thick. Cut into desired shapes and place on cookie sheet. Bake at 350 degrees for 8-12 minutes. Just until edges are golden brown. Let cookies cool completely before decorating.
For the frosting, cream butter, add sugar, milk, and vanilla. Mix until combined.