Mud Hen Bars

Mud Hen Bars are a delicious cookie bar recipe with marshmallows and chocolate chips.

The dessert bar recipe is simple to make and combines a chewy bottom with a crunchy top layer for the perfect treat. 

Original and Old Fashioned

I searched high and low for the origin of these ooey gooey bars. They are an old fashioned treat that have been around for a long time.

Who came up with the name? How did they come up with it? I really couldn’t find much. All we know for sure is that mud hen bars are delicious.

Why These Bars are Best

At the base of the dessert is a cookie-like layer, followed by a gooey marshmallow and chocolate chip layer, and finally topped with a crisp, brown sugar meringue.

The combination offers a wonderful contrast between the soft, chewy, and crispy layers.

Many people like them because they include a mix of both traditional and unexpected dessert flavors in one bar, making them a unique treat that stands out at gatherings, potlucks, or any dessert table.

Things You’ll Need to Make the Chocolate and Marshmallow Cookie Bars:

• Butter
• Sugar
• Vanilla
• Eggs
• Flour
• Salt
• Baking powder
• Chocolate chips
• Mini marshmallows
• Light brown sugar

Full printable recipe with measurements and instructions listed at the bottom of the post in the recipe card.

There are several ways to make the chocolate chip bars including the recipe I am sharing today. You can also make the mud hen bars with a brownie bottom, or even gluten-free bars. 

How To Make Mud Hen Bars

1. Grease the casserole dish.
2. Mix the softened butter and sugar in a medium-sized bowl and cream together.  
3. Next, add the vanilla, two egg yolks, and one whole egg and mix into the sugar mixture. Save the egg whites for the top layer.
4. Add the flour, baking powder, and salt and mix until well blended. 
5. Press the cookie dough into the greased 13″ x 9″ pan. 
6. Sprinkle the chocolate chips and marshmallows on the top. 
7. Finally, add the egg whites to another bowl and beat with the hand mixer until the egg whites form stiff peaks. Add the brown sugar and mix.
8. Spread gently on top of the chocolate chips and marshmallows. 
9. Bake approximately 30 minutes or until the top is brown and a cake tester comes out clean.

Step-By-Step Instructions For the Cookie Bars

Start by adding the softened butter to a bowl, and if you didn’t set the butter out to soften, you can put it in the microwave for about 15 seconds to help soften it a little. 

Next, pour the sugar into the bowl with the butter.

Add the whole egg and two egg yolks and mix everything together. Be sure to save the two egg whites for the top of the dessert. 

Next, you’re going to add the flour, salt, and baking powder and mix everything together. This will create your cookie batter. 

If you’d like to have a brownie bottom instead of a cookie, you can get the recipe for homemade brownies from scratch here. They are so chocolatey and delicious. 

Take the batter and spread it out into the greased casserole dish. It will be a very thin batter, but it will rise when it cooks. 

If you’re using a spatula to spread the cookie dough into the bowl, you can spray the spatula to keep the dough from sticking.

If you’re using your hands, you can even spray a little non-stick cooking spray on your hands. 

Once you’ve spread the cookie dough, sprinkle the chocolate chips over the dough. You can even add a few more if you’re a big chocolate lover. Is too much chocolate a thing? Never!

Next, sprinkle the marshmallows. Chocolate chips and marshmallows always remind me of S’mores, which I love to eat any time of year. 

Egg White and Brown Sugar Topping

Add the egg whites to a bowl. Make sure your bowl is clean and dry, otherwise the egg whites might not stiffen like they are supposed to (speaking from experience. More than once. You think I’d learn). 

Beat the egg whites until stiff peaks form. 

Then add the light brown sugar to the egg whites. 

Mix the egg whites and brown sugar together until blended. It only takes a few seconds to blend the two ingredients. Be sure not to over mix. 

Spread the egg white and brown sugar mixture on top of the marshmallow and chocolate chips and bake for about 30 minutes or until a cake tester comes out clean. 

Once the mud hen cookie bars bake, let them cool for a little while. 

Mud Hen Bars

Tips and Tricks for Making Mud Hen Bars:

• When you spread the cookie dough into the casserole dish, make sure you’ve greased the casserole dish so the cookie bars won’t stick. 
• Spray the spatula with a little non-stick spray to help press the dough down without sticking.
• Make sure the bowl is clean and dry when adding egg whites. If there is even a drop of water it can affect your whites and they will not stiffen like they are supposed to. 
• While baking, if the top begins to brown before the cookie has completed baking, turn the oven down about 25 degrees. 

Ways To Add Variety To Mud Hen Bars

Add some different flavor variations to the bars.

• Citrus: Add some lemon or orange zest to the cookie base for a pop of flavor.
• Coffee: Incorporate instant espresso powder for a coffee-flavored base and a zing of flavor.
• Almond: Use almond extract instead of vanilla for a nutty flavor.

Add some toppings to the bars.

• Drizzles: Once the bars are done baking, drizzle with caramel, chocolate, or raspberry sauce.
• Sprinkles: Add some colored sprinkles to the top for a more festive occasion.
• Sea Salt: A sprinkle of sea salt on top can bring out the sweetness and offer a salty-sweet contrast.