Chocolate Chip Meringue Cookies

It's hard to crack open a pastry cookbook without encountering at least one recipe that calls for the use of French meringue. Since the 17th century, cooks have been using it as a natural leavening agent (an ingredient that provides rise and structure) for all kinds of desserts, including angel food cake, souffle, pavlova, baked Alaska, Eton mess and baked meringue cookies, just to name a few.

French meringue is one of the most simple, yet mysterious elements in the world of pastry. It consists of only four ingredients: egg whites, sugar, acid, and salt. These ingredients alone may seem unremarkable, but when combined together with the most critical element, forceful whipping, they become a marvel of chemistry and confection.

There are whole chapters of books devoted to the science involved, but for the sake of brevity, here's the quick and dirty version. Egg whites are mostly composed of water and proteins. When they're beaten, the normally tightly wound-up proteins (mostly ovalbumin) begin to unravel and stretch out, allowing them to link up with each other. This network of protein reinforces tiny air bubbles formed in the watery whites, creating a thick foam. As you continue to beat, the protein-strengthened walls of these bubbles are stretched thinner and thinner as more and more air is introduced until a critical ratio of air to water in the foam is reached. Suddenly, the walls begin to fail and the meringue takes on a broken appearance similar to dull, lumpy clouds. The addition of acid (in most cases, cream of tartar) helps strengthen the bonds between proteins, while sugar adds viscosity to the water, both of which make for stronger bubbles and prevent this lumpiness from occurring.

What does all this mean to you, the cook? When making meringue, vigilance is key, which means watching the egg whites carefully as they whip, adding the other ingredients at the proper times, and adding the sugar steadily and in small amounts, to ensure that you are stabilizing the meringue while the sugar dissolves properly into the mixture. 

Cooks use all sorts of different approaches when making a French meringue, none of which are wrong, but I've found that the one here yields a reliably stable meringue with just a few tips.

Carefully Separate the Eggs

Clean and complete separation is critical for obtaining volume when whipping egg whites for meringue. The slightest trace of fat (which the yolks contain) will cause the meringue to be flat and useless. To be sure that you won't ruin an entire batch, separate the whites from the yolks one at a time in a separate bowl, then add them to the mixing bowl after each separation. This way, if you break one, you have only wasted one egg (but go ahead and have it for breakfast instead!)

Whip to Soft or Firm Peaks, as Needed

Different recipes will call for either soft peaks or firm peaks. Once the meringue looks big, glossy, and thick, stop the mixer and check to see if the meringue is at soft peak stage by dipping the whisk vertically into the bowl and pulling it up straight, then flipping it over. A "soft peak" will begin to slowly slump over while a firm peak will not move. If you are whipping to soft peaks, the meringue will begin to droop over a bit after being held sideways for five seconds. For firm peaks, the meringue should not move during this test. If the meringue has not reached the desired consistency, continue whipping at high speed for another 30 seconds to 1 minute, then stop and test again.