Preheat the oven to 350°F (175°C) and grease a 9-inch round cake pan.
In a medium bowl, whisk flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In a large bowl, beat the butter and sugar until fluffy.
Add the eggs one at a time, beating well after each addition.
Stir in the vanilla extract.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Gently fold in the chopped apples and cranberries.
Pour the batter into the prepared pan and smooth the top.
For the topping: Mix brown sugar, cinnamon, and melted butter. Sprinkle over the batter.
Bake for 35-40 minutes or until a toothpick inserted comes out clean.
Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.