Soft and Chewy Chocolate Chip Cookies

1. In a large bowl, cream together margarine or butter with both brown and white sugars, until well blended.
2. Add the egg and vanilla and beat well.
3. In a medium bowl, mix together the flour, baking soda, and cornstarch. Add this mixture to the butter mixture and stir to combine.
4. Stir in chocolate chips.
5. Chill dough in fridge for at least 30 minutes. Alternately, you could cover the bowl and let it chill overnight.
6. When ready to bake, preheat oven to 350 F.
7. Line a baking sheet with parchment paper. Place rounded tablespoons of dough onto lined cookie sheet, about 2 inches apart.
8. Bake one sheet at a time for 8-10 minutes. Remove from oven. They will look puffy and soft right out of the oven. Keep the rest of the dough in the fridge while the sheets are baking.
9. Let cookies cool on the baking sheet for at least 5 minutes, before moving them to a cooling rack to cool completely.