Cookie tips

These were from an email from, er, Cook's Illustrated I believe. I'm putting them here as reference.

• By adjusting key ingredients, you can change the texture of any cookie recipe.
• If you want chewy cookies, add melted butter. Butter is 20 percent water. Melting helps water in butter mix with flour to form gluten.
• If you want thin, candy-like cookies, add more sugar. Sugar becomes fluid in the oven and helps cookies spread.
• If you want cakey cookies, add more eggs. Yolks make cookies rich, and whites cause cookies to puff and dry out.
• If you want an open, coarse crumb and craggy top, add baking soda. Baking soda reacts quickly with acidic ingredients (such as brown sugar) to create lots of gas bubbles.
• If you want a fine, tight crumb and smooth top, add baking powder. Baking powder works slowly and allows for an even rise.