Preheat the oven to 350°F (175°C). Grease a 9 x 5-inch loaf pan or line it with parchment paper, leaving an overhang to make removing the loaf easier.
In a large mixing bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, salt, cinnamon, and nutmeg until well combined.
In a separate bowl, whisk the egg, milk, orange juice, oil, and orange zest until smooth.
Pour the wet ingredients into the dry ingredients and stir gently until only a few streaks of flour remain. Do not over mix.
Peel, core, and finely chop the apple. Fold the chopped apple and cranberries into the batter until evenly distributed.
Transfer the batter to the prepared loaf pan and smooth the top with a spatula.
Bake for 55 to 65 minutes, or until a toothpick inserted into the center comes out clean or with just a few moist crumbs. If the loaf begins to brown too quickly, loosely tent it with aluminum foil during the final 15 minutes of baking.
Allow the loaf to cool in the pan for 10 to 15 minutes before transferring it to a wire rack to cool completely.
To make the glaze, whisk together the confectioners' sugar, orange juice (or milk), and orange zest, if using, until smooth. Add a little more liquid if needed to reach a drizzling consistency. Spoon or drizzle the glaze over the cooled loaf before slicing and serving.