1 cup butter, at room temperature
½ cup sugar
½ cup packed brown sugar
2 large eggs
1 teaspoon pure vanilla extract
2 cups unbleached white pastry flour
½ teaspoon salt
1 teaspoon baking soda
½ teaspoon baking powder
2 cups rolled oats
12 ounces semi-sweet chocolate chips (about 1 ½ cups)
Option: Add 1 cup of raisins and/or ½ cup of coarsely chopped toasted walnuts.
Preheat the oven to 350º.
In a large bowl, thoroughly cream the butter, sugar, and brown sugar with an electric mixer. Add the eggs and vanilla and beat well. In a separate bowl, combine the flour, salt, baking soda, and baking powder. Add the dry ingredients to the butter and sugar mixture and blend well. Mix in the oats. Using a large spoon or your hands, fold in the chocolate chips, and the raisins and walnuts, if using. The dough will be fairly stiff.
On un-oiled baking sheets, drop generous rounded teaspoonfuls of dough about 4 inches apart. Bake for about 12 minutes, until golden. Cook completely before storing in a sealed container.