Add the oats, flour, baking powder, cinnamon, and salt to Basic Recipe dough. Wrap with plastic wrap and chill for one hour.
Preheat the oven to 350°F.
Roll out the chilled dough onto a piece of parchment paper to a 13x9-inch rectangle. Transfer the parchment paper to a baking sheet. Bake until golden brown, about 15 minutes. Lift the parchment paper onto a rack, and cool completely.
Decorate the top of the cooled cookie with Royal Icing that has been thinned with 1 tsp. water. Use a pastry brush to apply an even layer of the Royal Icing almost to the edges of the cookie, reserving any extra. Let the icing dry completely before decorating, at least 3 hours.
Spoon about 1/2 tsp. of the luster dust in a small ramekin. Add enough orange extract to make smooth, about 1/2 tsp. Add 1/4 tsp. of extract if the mixture is too thick. Paint the desired pattern on top of the hardened Royal Icing with a clean craft brush. Repeat with remaining colors. Attach the small candies as lights on the tree with any remaining Royal Icing. Cut or break the cookie into pieces.
In a medium bowl combine the flour, baking soda, and salt.
In a separate large bowl beat the butter and sugars with an electric mixer until light and fluffy, about 2 minutes. Add the eggs, one at a time, beating well after each addition. Beat in the vanilla. Gradually add the flour mixture, beating until just combined.
Divide the dough in half, and proceed with a cookie recipe. (Each recipe uses half of the Basic Recipe.) To save the dough for later use, shape each half into a disc, wrap in plastic, and freeze for up to a month.