Sift together the two flours, 5 Tablespoons of the sugar, baking soda cream of tartar, and the salt. Sift two more times, then place in a mixing bowl. Add cream and stir until the mixture holds together. Turn onto lightly floured surface and knead twelve times. Roll dough to ¾ inch thick. Cut into desired shapes, cover tightly in plastic wrap and chill overnight in refrigerator. In the morning, brush with milk and dust with sugar. Bake 12-15 minutes until lightly brown. Serve warm.