Preheat the oven to 350℉/180℃. For easy removal of the bars, place parchment paper on the bottom and 2 sides of the pan. Then grease the other two sides and then set aside. Melt the butter and allow it to cool for 15 minutes while you prep the rest of the ingredients.
2/3 cups butter
In a large-sized bowl, add in the flour, baking soda, baking powder, cornstarch, and salt. Mix together.
1 3/4 cups all-purpose flour, 1/2 tsp baking soda, 1/2 tsp baking powder, 1 tbsp cornstarch, 1/4 tsp salt
In a large bowl, add melted and slightly cooled butter, oil, brown sugar, and white sugar. Whisk to combine.
1/4 cup oil, 3/4 cups dark brown sugar, 1/2 cup white sugar, 2/3 cups butter
Into the same bowl, add the eggs and vanilla. Whisk to combine, about 2-3 minutes. There should be some air bubbles.
2 large eggs, 1 tbsp vanilla
Toss in the dry ingredients and using a spatula, gently fold to combine. Don't completely mix it in yet, leave some dry streaks.
Stir the coconut in until no dry streaks appear.
1 3/4 cups unsweetened shredded coconut
Transfer the batter into the prepared pan and spread evenly. Sprinkle some white sugar on top (about 1-2 tsp, this is optional but recommended). Bake for 28-35 minutes or until a toothpick inserted comes out clean. Mine took 32 minutes.
The bars will have a slight golden edge, and a soft middle when they are done. These chewy coconut bars are so good! Allow them to cool, slice, and enjoy!
They stay good on your counter for 2 days, and in airtight container for 1 week.