Bar Cookie Tips
Bar Cookies are a cross between cake and cookies and are made from a soft dough or ingredients that are spread or layered in a rectangular or square pan. They can be crisp or chewy; filled or layered. They are baked in sheets and then cut into squares or bars. Most drop cookie dough can also be made into bar cookies.
Many multiple layer bar cookie recipes call for a crust that is partially baked first then the filling and topping are placed on top of the hot crust and returned to the oven for additional baking to prevent the crust from becoming soggy and undercooked.
These are the easiest cookies to bake, because several batches are baked at once. Common pan sizes used to make bar cookies include an 8" x 8" x 2" baking pan, a 13" x 9" baking pan, or a 14" x 10" jellyroll pan, depending on what the recipe specifies.
Tips for making the perfect bar cookies
Generally, ingredients are stirred and not beaten unless the recipes indicates otherwise. The ingredients are combined until they are just blended. Over-beating will cause them to rise too much, too fast with the result that they will fall and crack as they cool. Over-beating recipes that call for flour will develop the gluten in the flour producing tough bar cookies.
Bar cookies made with tub margarine will be very thin and oily due to tub margarines high liquid content. Do not use light or whipped margarine either. The low fat, high water content of these products will produce unsatisfactory results.
Always use the pan size called for in the recipe. Using a different size will affect the cookies texture; a smaller pan will result in a more cake-like texture and a larger pan will produce a drier texture.
Use Pan Release, vegetable shortening, or nonstick vegetable spray. Butter may cause bar cookies to stick and over brown on the bottom.
The batter or dough should be spread evenly into the bottom of a shallow baking pan.
When using a glass baking pan instead of one made of metal, reduce the oven temperature by 25°F (10°C).
Baking timings are equally important. Over baking dries out the bars and makes them dry and crumbly.
To allow for fluctuations in oven temperatures, be sure to check your bar cookies at least a couple minutes before the minimum baking time suggested has elapsed.
Generally, bar cookies are done when a wooden pick or cake tester inserted in the center comes out clean or a moist not wet crumb is adhered to it.
Before cutting, most bar cookies should cool in the pan on a wire rack until just warm. To make serving easy, remove a corner piece first, and then remove the rest.
With the exception of bar cookies made with a delicate shortbread base, like lemon bars, cutting can be made easier by lining the baking pans with heavy-duty aluminum foil to insure easier removal later. For best results be sure to extend the foil at least 2" over the pan leaving enough overhang on the two opposing ends to use as handles. The easiest way to shape the foil is to turn the pan upside down, and then smooth the foil around its contours until the right shape is achieved. Then turn the pan over and slip the foil into the pan.
Use a large sharp chefs knife to trim away the outer dry edges of the bars before cutting them, wiping the blade clean with a damp towel after each cut.
Ideally bar cookies should be cooled and stored right in the baking pan, though most are cut after they've cooled. The exception is crisp-style bars, which must be cut while warm--before they crisp--to prevent unsightly crumbling.
To store, cover bar cookies with plastic wrap or aluminum foil to prevent them from drying out. They can also be stored in an airtight container.