Preheat your oven to 350°.
Mix oil, butter, and sugars. Beat until creamy.
1 c. vegetable or canola oil, 1/2 c. butter, 1 c. sugar, 2 c. brown sugar
Add eggs and vanilla. Beat well.
5 large eggs, 2 tsp. vanilla extract
Mix flour, soda, salt, and cornstarch in a separate bowl. Add to the wet ingredients and mix.
2 tsp. baking soda, 2 tsp. salt, 4 1/2 - 5 c. all-purpose flour, depending on how thick you like your cookies, 1 Tbsp. cornstarch
Stir in the chocolate chips.
2 c. chocolate chips
Drop onto greased cookie sheets with a cookie scoop or by a rounded teaspoonful.
Bake for 10 minutes or until very lightly browned.
Cool on a wire rack.
Store in an airtight container.