Preheat oven to 350°F (175°C) and grease a 9x13 inch baking pan.
Whisk together flour, baking soda, salt, and cinnamon in a medium bowl.
In a large bowl, beat eggs and granulated sugar until pale and thick, then whisk in oil and vanilla.
Fold the dry ingredients into the wet mixture until no dry streaks remain.
Gently fold in the diced apples and 1/4 cup of the pecans.
Transfer batter to the baking pan and spread evenly.
Combine remaining pecans and brown sugar; sprinkle over the top of the batter.
Bake for 45 to 50 minutes until a toothpick inserted into the center comes out clean.
Allow to cool for 15 minutes, then drizzle salted caramel sauce over the top.