Preheat the oven to 350 degrees. Grease a square (8x8 or 9x9) baking pan and set it aside.
Mix the apple chunks with the sugar in the large bowl, and let them stand for 15 minutes. That interval gives the apple chunks time to absorb the sugar.
In a medium bowl, mix (or whisk) together the flour, baking soda, cinnamon and salt.
After the 15 minute "rest" for the apple and sugar mixture, lightly beat the egg in the small bowl and add the oil and egg to the apples and sugar.
Add the dry ingredients to the apple, sugar, oil and egg mixture in 3 additions, mixing thoroughly after each addition. By the end, the batter will be stiff. Fold in the chocolate chips and spoon the batter into the greased baking pan. (It's too stiff to pour.) Even it out with the spatula or the back of the spoon.
Bake the cake 30-40 minutes, until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan, on a wire rack, before cutting and serving.