This is my favorite recipe for Cowboy Cookies that I got from my Moosewood Restaurant Book of Desserts, one of my favorite dessert cookbooks.
1 cup butter, at room temperature
1/2 cup sugar
1/2 cup packed brown sugar
2 large eggs
1 tsp. pure vanilla extract
2 cups unbleached white pastry flour (I substitute 2 cups minus 2 T. all-purpose flour)
1/2 tsp. salt
1 tsp. baking soda
1/2 tsp. baking powder
2 cups rolled oats
12 ounces semi-sweet chocolate chips
Preheat the oven at 350 degrees.
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. The dough will be fairly stiff.
On unoiled baking sheets, drop generous rounded teaspoonfuls of dough about 4 inches apart. Bake for about 12 minutes, until golden. Cool completely before storing in a sealed container.
Variation: Add 1 cup of raisins and/or 1/2 cup of coarsely chopped toasted walnuts.