Cream two room-temperature sticks of unsalted butter with a good amount (about 1.5c) brown sugar. A mixer is good, but a wooden spoon works too.
Creaming creates little air pockets in the fat. The color will lighten as more air is introduced, but individual sugar granules will still be visible.
Add a nice quantity of vanilla, and two eggs. Beat a bit more.
Mix in oats to taste, and a couple of tablespoons of cocoa powder. I tend to use close to a cup of oats. Now is also the time to add chopped nuts, fresh or dried spices (allspice, cardamom, cinnamon, ginger, etc), coconut, or citrus zest.
Slowly add flour while stirring until the texture seems right, usually no more than 2c. A thick batter will make a chewier, cakier cookie; thinner will spread more and be more like shortbread. Keep in mind that extra oats and dry ingredients lower the amount of flour you need to add.
Add chips. I've used both white and semi-sweet chocolate chips.
Perform frequent quality control tests.
Scoop cookies onto ungreased pans and bake at 325F.
Remove when just golden and dry at the edges, and spatulate onto a wire rack to cool.
Bio:Eric J. Wilhelm is the founder of Instructables. He has a Ph.D. from MIT in Mechanical Engineering. Eric believes in making technology accessible through understanding, and strives to inspire others ...read more »