Preheat oven to 375° Fahrenheit.
Line a bar pan with parchment baking paper.
Place chia seeds and water in a small bowl and stir. Set aside to soak for at least 5 minutes.
In a separate bowl, stir together the white whole wheat flour, oat flour, baking soda, and salt. Set aside.
Place the sugar, brown sugar, olive oil, and vanilla in a medium mixing bowl (or the bowl that comes with your stand mixer, if using) and mix well. Either use a whisk (if mixing by hand) or the paddle attachment of your stand mixer.
Add chia mixture (it should have a gel like consistency before adding). Mix well.
Add half of the flour mixture and mix until most is incorporated.
Add the rest of the flour mixture and mix just until all flour is incorporated.
Stir in chocolate chips.
Spread dough out evenly over the bar pan by pressing down firmly with the palm of your hand.
Bake in the oven for about 22 minutes or until the edges are golden in color.
Remove from oven and let cool before slicing into squares.