Mookie's Whoopie Pies (aka, the Mookie Pie)

Whoopie pies, the official treat of Maine, have been hip on the national scene for years now. There are all sorts of flavors, like pumpkin, lemon, orange, maple, and gingerbread, as entrepreneurs seek to make a buck selling this trendy new treat. The only problem is that what they're selling aren't as good as the whoopie pies of my youth.
What makes something a whoopie pie? Well, yes, an original whoopie pie has vanilla filling between two chocolate cookie-shaped cakes, but the whoopie pies you buy now are so far removed from the homemade treats of my childhood that they are simply not worth buying.
If you buy a whoopie pie now, it will probably have a simple sugar-shortening filling flavored with vanilla, but the problem with this filling is that the sugar and shortening are always a little out of balance. With some pies, the filling is too sweet. With others, too greasy. My mother's whoopie pie filling doesn't suffer from this imbalance because part of the structure of the frosting comes from egg whites.
The addition of egg whites gives the filling body without simply adding more sugar. Even better, while the frosting that fills many whoopie pies now can be oily. The egg whites in my mother's recipe make the frosting spreadable and light, but it also dries a bit around the edges creating a texture I love, but also helps to keep the filling from oozing out when you take a bite.
But it's the cake that really sets a traditional whoopie pie apart from the imitations sold around the state now. Today's cakes are often spongy like cupcakes. When you take off the wrapper, the cake sometimes sticks to the wrapper and even to your fingers when you eat them. IMHO, a traditional whoopie pie just shouldn't do that. My mother's whoopie pies were soft when you bit them, but they were dry on the outside, almost crusty. The contrast between the crusty edges and the soft middles is what made them special.
One more thing. Whoopie pies now are huge compared to the ones made when I was growing up. They were so big that eating one would send your blood sugar soaring.
So, I decided to make half a batch of my mother's recipe to see if they were everything I remembered. I made them too big, though, and a half batch made only three pies. I took one to share with my sister, and we were happy with the results, for the most part. The frosting was perfect, and the texture of the cake was good. It was certainly tastier than the whoopie pies you can buy in stores now. But I wanted something a bit more chocolatey. Whoopie pies are traditionally made with cocoa, but I thought if I could incorporate chocolate in addition to the cocoa into the batter, I would have a better tasting cake with the right texture.
My first effort was a success and a failure. The cakes ended up tasting great, but they were thin and had the texture of soft, fudge cookies. The tops were crackled. They were delicious, but too hard to eat in a whoopie pie. I also made a proper buttercream frosting just as an experiment, but the butter made it far too rich--and soft.
My second batch was more cakey and less fudgy. The cakes were perfect. But I decided to experiment with the icing, and that didn't work. I wanted to find out if it would come out the same with powdered egg whites instead of fresh, as I know that some people might be nervous about eating frosting made with raw egg whites. The result tasted okay, but was far to soft.
The third batch, I made with the original frosting recipe and the cake recipe from the second batch. The results? Yummy. I even made them smaller so a person could eat one without feeling too guilty for overindulging. And even though they are closer to what I remember eating as a child, I decided to call them Mookie pies since they are fudgier than the originals.

A classic Maine whoopie pie

Here's the recipe. Preheat oven to 350 degrees.
Cake Ingredients:
2 oz. unsweetened baking chocolate
2/3 c. milk
2 t. vanilla

2-1/8 c. all-purpose flour
3-1/2 T cocoa
1/4 t. salt
2/3 t. baking soda
1 t. baking powder

1/2 c. soft butter
1/3 c. shortening
1-1/3 c. granulated sugar
1 large egg
2 large yolks (reserve 2 whites for filling)

In a saucepan over low heat, melt the chocolate in the milk. Whisk in vanilla till well mixed. Set aside till lukewarm. If you have a warm* kitchen, you might want to set the chocolate milk in the refrigerator. If the shortening mix below is too warm and the milk is too warm, the fats can soften (start to melt), resulting in a cake that spreads too wide.

In a medium bowl, sift together flour, cocoa, salt, soda, and powder.

In a large bowl, cream the fats and sugar, then beat in the egg and yolks till well incorporated. Again, if you have a warm* kitchen, consider chilling the beaters and bowl to keep the fats from softening too much when creaming.

Mix the dry into the creamed with beaters till well mixed. It should not be smooth at this point. Then blend in chocolate milk mixture just till well blended. It will be smooth, but very thick.

Spoon 1/8 cup of batter (I use a cookie dough scoop) onto ungreased cookie sheets leaving space between cakes. I get 11 on each sheet--a row of three between two rows of four. If you're not worried about them spreading too much and touching, you could try to get more on the sheet. This makes either side of 36 cakes for half that many whoopie pies.  

If you'd like to make these larger, try using 1/3 cup per cake. If you do, you might fit them all onto two cookie sheets. This makes 6-8 whoopie pies (12-16 cakes, 6-8 per sheet).

I have found that the third sheet tends to rise higher. I'm not sure why this is, so I have taken to scooping out the cakes then letting them sit on the pan for about 15 minutes. 

Bake in the middle to top of the oven. If baked on the bottom rack, they might burn on bottom. Bake the larger ones for about 16 minutes, the smaller, for about 14 minutes. The larger ones should have a somewhat rounded top that is dry to the touch. The smaller ones will not round up as much. If you take them out too late, they'll be dry. If you take them out to early, they'll likely fall and be more like soft cookies. When done, remove from the oven and let sit for a couple minutes before using a spatula to remove them from the cookie sheets and put them on wire cooling racks.

Filling Ingredients:
2 egg whites
2 t. vanilla
1/2 c. shortening
pinch of salt
2-1/2 c. confectionary sugar

With an electric beater, beat the egg whites, vanilla, shortening, salt, and 1 cup of the sugar till well mixed. Gradually beat in the remaining 1-1/2 cups of sugar. If the filling has the right amount of sugar in it, it should give some resistance to the beaters. The goal is a filling that stands up well, sort of like firm peaks, vs. soft peaks, though they won't really look like beaten cream or beaten egg whites. 

Putting them together:
After the cakes have cooled, spoon some frosting one one cake and press it down with another cake. How much frosting you use is up to you, but I sometimes have frosting left over. I think the small ones taste good with 1/4 to 1/3 inch of frosting, while the larger cakes take 1/3 to 1/2 inch of icing.

Leave the cakes out for a few hours so that the icing can dry a bit. After they've set well, you can keep them in a container on the counter or wrap them individually in plastic. They are best eaten in a day or two. They can also be wrapped and frozen to eat later.

Once you're comfortable with this recipe, you might add other flavors to the filling, perhaps almond extract, mint, cherry...

Enjoy!

*Warm kitchen could be as low as 70 degrees. Usually, my kitchen is about 60 degrees in winter. I have tried cooling the sheets of batter in the refrigerator for 10 or 15 minutes or so before baking them. This seems to work to keep the batter from spreading too much, and it's certainly easier than chilling all the utensils and cooling the chocolate milk.