Fun Christmas sugar cookies that you can use as a base for writing a letter to Santa (with an edible writing pen). Adapted from Delicious Table, Land O' Lakes, and Sweet Jenny Belle.
In a large mixer, cream the butter and sugar. Add the egg, baking powder, orange juice, and vanilla, and continue mixing. Mix in the flour until a soft dough is formed. Wrap the dough securely in plastic wrap and chill in the refrigerator for at least one hour.
Remove dough from refrigerator, turn out onto a floured board. Roll out dough to 1/4" thickness. Cut into squares using a square cookie cutter or plastic container lid. Place cookies on a parchment paper lined cookie sheet. Bake at 400 degrees for 10 to 12 minutes, or until lightly browned (watch carefully!). Cool cookies on a baking rack.
Place all ingredients in mixer and blend on low speed for ten minutes. Cover icing with plastic wrap or a towel until ready to use (unused icing may be stored in the refrigerator if covered securely).
Fit a pastry bag with a round tip and fill the pastry bag with icing. Pipe a line around the edge of the cookie. Fill in the rest of the cookie with icing and carefully spread the icing so it is flat across the cookie in a nice square shape. Set the cookies in a dry and safe place and let the icing set for at least 24 hours.
Using a ruler, carefully draw the red vertical line and the blue horizontal lines for the writing paper. Then give the pens to your family and let them write to their hearts' content.