Using an electric mixer, cream butter and sugar until light; add the egg, brandy, and vanilla and beat well. Add the dry ingredients a little at a time and mix well until blended. Wrap and chill the dough for at least 30 minutes before rolling.
Preheat the oven to 400 degrees. On a lightly floured board, roll out one third of the dough at a time (keeping the rest in the fridge). Roll to about 1/4 to 1/6 inch thick and cut out with cookie cutters. x
Put shapes on parchment lined (or greased) baking sheets (place in freezer in between batches) and bake for 6-8 minutes, depending on the size of the cookie. Cool on racks.
Once completely cool decorate with Royal Icing.
For the Royal Icing
Mix together the sugar, egg whites and lemon juice. Separate the icing out into however many colors you'd like to have (you can separate into bowls or zip lock bags.
Add food coloring slowly until desired color is attained. If using zip lock bags you can cut off a small bit of the corner of the bag to pipe out the icing onto the cookie.
Decorate the cookies with the icing, then quickly top with sprinkles before it drys.
Store finished (and dried) cookies in a air tight container at room temp for 1 week. Or freeze.
If you can find a fondant or icing sugar, that will work best. Otherwise just sue powdered confectioners sugar.