Prep. Preheat your oven to 375°F (190°C), placing an oven rack in the middle position. Then, line cookie sheets with parchment paper or silicone baking mats.
Beat the wet ingredients. In a large mixing bowl, use an electric mixer to cream the softened butter, sugar, egg, and vanilla extract until the mixture is light and fluffy.
Combine the dry ingredients. Whisk together the flour, baking powder, and salt in a separate bowl. Then, gradually add the dry ingredients to the wet mixture, mixing until just combined for a tender dough.
Add the goodies. Gently fold in the chopped cranberries, orange zest, and nuts (if using) until evenly distributed throughout the dough.
Portion the dough. Using a cookie scoop or tablespoon, drop rounded portions of dough onto your prepared cookie sheets, spacing them about 2 inches apart to allow for spreading.
Bake. Place the cookie sheets in the oven and bake for 12–15 minutes or until the cookies are lightly golden at the edges.
Cool. Allow the cookies to cool on the cookie sheets for a few minutes before transferring them to wire racks to cool completely.
Glaze. In a small bowl, combine the powdered sugar with 1–2 teaspoons of cream or milk, stirring until smooth. Adjust the consistency with more cream or milk until the glaze is thin enough to drizzle. Drizzle over cooled cookies and let the glaze set for a few minutes before stacking or serving.