Make the cookie base recipe, adding the cranberries, pecans, and rum.
Spread the batter in a buttered or parchment-lined 9-inch square baking pan. Bake for 35 minutes. Transfer pan to a wire rack. Cool for 10 minutes before slicing.
To Make Now and Bake Later: When you mix a batch of cookies, double the recipe. Bake half the dough according to the recipe and divide the rest into 4 equal portions. Roll each portion into a log about 1 1/2 inches in diameter. Wrap each log in plastic, then place in a resealable plastic bag. To save yourself time and hassle, label the bag with the flavor, the oven temperature, and the baking time, adding 3 to 6 minutes to the regular oven time. Freeze the dough for up to 3 months. To bake, slice the frozen dough into rounds about 1/2 inch thick, making as few or as many as you would like. Bake on a parchment- or foil-lined baking sheet.