Preheat oven to 400 degrees F.
In a large bowl, whisk sugar and oil until well combined.
Add remaining wet ingredients and whisk to combine.
In a separate bowl, combine dry ingredients except chocolate chunks.
Add dry ingredients to wet and fold until just combined. Batter will be thick.
Line a muffin pan with 12 liners. Fill liners 3/4 of the way full with batter. Top with chocolate chunks if desired.
Bake for 15 or until muffins are completely cooked through.
Let cool in pan for several minutes before transferring to a cooling rack.
Enjoy!