Lemon Cookie Bars (Made With a Box of Cake Mix)

We saw this recipe going around and making people lose their minds over how easy it was, so we had to try it ourselves, and it earned a permanent spot in our recipe rotation. Keep scrolling for the full ingredient list, the step by step directions, and a few tips I picked up after making these more than once.

If you are a cream cheese dessert person, you will also want to check out my No Bake Cherry Cheesecake Bars.

Why These Lemon Cookie Bars Went Viral

I think it comes down to how unbelievably easy this is. You are not whisking a separate cookie dough from scratch. You are not zesting six lemons. You open a box of cake mix, melt some butter, crack a few eggs, and you have a dessert that looks like it came from a bakery case. My daughter actually requested these for a school event and watched the entire tray disappear before she even got a piece, which tells you everything you need to know about how fast people go for these.

What You Need for the Cake Mix Crust

• 1 box (15.25 oz) lemon cake mix
• 1/2 cup (1 stick) butter, melted
• 3 eggs, divided
• 1 block (8 oz) cream cheese, softened
• 16 oz powdered sugar
• 2 tablespoons lemon juice

A quick note on that cream cheese. Let it sit out on the counter while you handle the crust layer. Cold cream cheese will leave little lumps in your topping no matter how hard you beat it, and a smooth topping is what gives these bars that pretty, almost custard like finish on top.

How to Make Lemon Cookie Bars

Heat your oven to 350 and give a 9×13 baking dish a good spray with nonstick cooking spray. Set that aside while you get going on the layers.

For the bottom layer, add the lemon cake mix, melted butter, and just one of your eggs into a bowl. Mix this well. I want to warn you now, it is going to look more like cookie dough than cake batter, thick and a little stiff. That is exactly right.

Pour it into your prepared pan and use your fingers to press it firmly and evenly across the bottom. This is your cookie base, so do not rush this part. An even layer means an even bake.

In a separate bowl, add the softened cream cheese, your remaining 2 eggs, the powdered sugar, and the lemon juice.

Beat this until it is completely smooth with no streaks of cream cheese left. Pour this mixture over your crust in the pan and spread it out evenly all the way to the edges.

Bake for 25 to 30 minutes, just until the edges start to turn brown. The center will still look soft and a little jiggly when it comes out, and that is normal.

Resist the urge to cut into these warm. I know it is hard. Let the pan cool completely on the counter before you slice, or the topping will not set up the way it should and you will end up with more of a lemon mess than lemon bars.

Tips for the Best Lemon Cake Mix Cookie Bars

These bars firm up even more after a few hours in the fridge, so if you like a cleaner cut, chill the whole pan before slicing. I usually run a sharp knife under hot water and wipe it dry between cuts to keep the lines crisp for photos, though honestly nobody at my house has ever complained about a messy piece.

Store any leftovers covered in the fridge, and pull them out about ten minutes before serving so the topping is not ice cold. These also freeze well if you wrap individual squares tightly, which is great news if you want to make a batch ahead for a party.

If lemon is your thing, you already know these need to be on your dessert table. And if you somehow have not tried the viral lemon cookie bars everyone has been talking about, now is your chance to see what the fuss was about.

Looking for another easy bar to add to your rotation? My Gooey Chocolate Caramel Cookie Bars Recipe is just as simple and just as loved.