Preheat oven to 350 degrees Fahrenheit (or 325 if using a convection setting).

In a large bowl, cream:
1 stick unsalted butter at room temperature
1/2 cup shortening

Beat in:
1 and 1/4 cup firmly packed dark brown sugar
3/4 cup normal white sugar

Add:
2 large eggs
1 tsp vanilla (I like double-strength)

Beat vigorously until it stops looking soupy– it ends up looking a little bit stiff and a little bit fluffy.

Add:
2 and 1/4 cups flour
1 tsp baking soda
1 tsp baking powder
1 tsp salt

Stir till it’s completely mixed.

Pour in:
1 cup (overflowing) chocolate chips.

Mix thoroughly.

Drop onto ungreased cookie sheet. Bake for about 13 minutes. Let cool on the sheet for two minutes, then use a spatula to transfer them to a cooling rack. Eat as soon as they won’t burn your tongue.

If you use a jelly roll pan for your cookie sheet, and you put 15 cookies on the sheet, this recipe makes about 45 cookies.