Preheat your oven to 350℉. Grease your baking dish.
In a bowl, combine the flour, baking powder, and ½ tsp of cinnamon. In another bowl, mix the remaining 2 tsp of cinnamon and 2 tbsp of sugar, and set it aside.
In a large bowl, mix the ½ cup of sugar, the brown sugar, and melted butter, mixing to combine until smooth. Add in the egg and vanilla and mix. Finally, add in the flour mixture and mix until mostly combined. Add the pecans and apple chunks and finish mixing.
Pour your mixture into your baking dish and spread it out. Sprinkle the top with the cinnamon-sugar mixture, as much or as little as you like.
Bake for 30-35 minutes. It's hard to tell for sure when it's done, but try to find a section of cake to test. Note that the kind of apple you use makes a difference, and a juicier apple will take a bit longer to bake.
Let cool and enjoy! Optionally, make a quick icing out of milk and powdered sugar to drizzle over the top.