In a large mixing bowl, cream together the butter, granulated sugar, and light brown sugar until light and fluffy, about 3-4 minutes. Add the egg and vanilla extract, mixing well to combine.

Gradually incorporate the baking powder, baking soda, salt, and cinnamon, followed by the all-purpose flour and old-fashioned oats until just blended. Fold in the white chocolate chips and dried cranberries.

Cover the cookie dough with plastic wrap and refrigerate for 30 to 60 minutes.

Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.

Using a medium cookie scoop, portion out the chilled dough into mounds, placing them 2-3 inches apart. Press each dough ball down slightly and sprinkle extra white chocolate chips and cranberries on top.

Bake for 10 to 12 minutes until the edges are just set and the tops start to turn golden. They should look slightly soft in the center.

Allow the cookies to cool on the baking sheet for 3 to 5 minutes, then transfer them to a wire rack to cool completely.