Preheat oven to 350 degrees F and line a baking sheet with parchment paper.
In a medium bowl, cream together the butter, margarine, and sugars until light and fluffy. Add the egg, corn syrup, and vanilla extract and mix until combined.
In another bowl, whisk together the flour, salt, and baking soda.
Slowly add the dry ingredients to the wet ingredients and mix until just combined. Add in the chocolate chunks and mix until evenly distributed.
Drop spoonfuls of cookie dough onto the prepared baking sheet about 2 inches apart from each other. Bake for 12-15 minutes or until edges are lightly browned.
Let cool on the baking sheet for 5 minutes before transferring to a cooling rack.