Preheat oven to 350°.
Place eggs, oil, melted butter, and vanilla into your mixing bowl. Mix well until nice and creamy.
5 large eggs, 1 1/2 c. vegetable or canola oil, 1/2 c. melted butter, 2 tsp. vanilla extract
In a separate bowl, whisk together the flour, sugar, salt, baking powder, and baking soda. Add brown sugar, quick oats, and chocolate chips.
4 c. all-purpose flour, 1 c. white sugar, 2 tsp. salt, 2 tsp. baking powder, 2 tsp. baking soda, 1 3/4 c. brown sugar, 4 c. quick oats, 1 1/2 c. chocolate chips
Stir together the wet and dry ingredients until well mixed.
Spread onto a greased 13 x 18" sheet pan. (1/2 sheet pan, not jelly roll pan)
Bake for about 20 minutes or until set and lightly browned.
Cool before cutting into bars.
Store in an airtight container. Freeze whatever you won't get to eat within a few days.