Start by making the batter in a large mixing bowl, cream together the butter, brown sugar, and sugar. Mix well.
Then add in the eggs, vanilla, flour, baking powder, salt, and a half and half, mix well.
Pour the batter into a prepared pan (a pan that oven-safe and has been sprayed with either olive oil or non-stick cooking spray)
Then make your topping in a large bowl (or the same bowl that you made the batter in) add the flour, brown sugar, butter, and ground cinnamon. Then fold in the diced pecans.
Spread the topping over the batter. Place the pan into the air fryer tray or basket. Set the temperature to 320 degrees F, air fryer setting, or air fryer crisp, for 12 minutes.
Note: The exact time is going to depend on a few factors, the size of the pan you used, obviously the smaller pan you use, the faster it will air-fry, and the air fryer model you have. If the cake is not made, after the 12 minutes, add another 5 minutes, and keep on air frying until the toothpick you stick in the middle of the cake comes out clean.
Let rest before cutting into the cake.
Plate, serve and enjoy!