oatmeal cookie squares recipe

Oatmeal Cookie Squares by Nana Haines

I’ve been eating these oatmeal cookie squares for as long as I remember. I used to be able to mix them up between innings and have them to snack on during the second half of the game.

Here is my current, modified recipe. Photos are for the modified recipe. The original recipe is at the end of the post.

oatmeal cookie squares recipe

We’ve known these as oatmeal bars and cookie squares.

Cookie Squares: Current Recipe

Here is my current recipe for these oatmeal cookie squares. The choice of flour type varies depending on what we have on hand and what I feel like.

  • Makes: This recipe makes a 9×13 pan of cookie squares.
  • Time: 90-120 minutes. (5-10 minutes to make the batter. 40 minutes to bake. 30-60 minutes to cool.)


  • 1.5 cups of butter (3 sticks) unsalted
  • 2 cups of panela (brown sugar)
  • 1 cup cane sugar (white sugar)

I put the butter sticks in a bowl and microwave for 30-60 seconds to soften them before creaming.

Preheat the oven (350 F): Because they mix up so quickly, I preheat the oven while softening the butter. I usually have the mix ready by the oven reaches temperature.


  • 2 eggs
  • 3 tsp of homemade vanilla
  • 1/2 cup of yogurt
  • 1/4 cup of water
cream ingredients
Cookie square batter with sugar, butter, eggs, vanilla, milk, and water

Mix in:

  • 2 cups of flour (cassava, almond, buckwheat, plantain)
  • 1 tsp of baking powder
  • 1/8 tsp of salt
  • 4 cups of oatmeal
  • Add 1 pkg of chocolate chips
cookie squares batter in mixer
Oatmeal cookie squares batter in mixer, ready to bake
cookie square batter in 9x13 pan
Cookie square batter in 9×13 pan, ready to go into oven

Bake at 350 F for 40 minutes.

cookie squares in over
Batter going in the oven
cookie squares cooked
40 Minutes Later… Cookie squares about to come out of the oven

The squares will be somewhat liquidy when they come out of the oven, but the top will be nicely browned. If you leave them in the oven until they firm up, they will be overcooked.

Allow squares to cool until cool.

While warm squares are delicious, they will be gooey and will not have any structure. The remaining squares will ooze out into the opening.

Once chilled, these squares will hold their shape well.

Recipe Variations

  • Variation: Sometimes I add large chunks of chocolate to the top of the batter before putting in the oven. Usually a dark chocolate (70% cacao) from a chocolate bar.
  • Variation: A few months ago, I tried cooking this recipe as cookies. Without gluten, they didn’t stay together. Good flavor, but frustrating (crumbly) texture.
  • Variation: I also tried adding chia seeds and psyllium husk powder to make them hold together a little better. I didn’t like the chia seed texture. And neither ingredient made an improvement to the squares.

Gluten-Free: This modified cookie square recipe is gluten-free. Just ensure that your rolled oats are actually gluten-free. The flours we usually use are gluten-free.

This recipe will work with wheat flour if desired.

oatmeal cookie squares ready to eat
Oatmeal cookie squares fresh out of the oven and ready to eat

Next Time:

Next time, add less/no water and see how it affects the final product. I originally added water because I used yogurt instead of milk, which I assumed to have less water content.

Original Recipe for Oatmeal Bars

Here is the original recipe, from our wedding gift cookbook that Sarah made for us. It is full of recipes from family and friends.

oatmeal bars original recipe
The original recipe for oatmeal bars

Use a 9X13 pan.


  • 1.5 cups of shortening
  • 1 cup white sugar
  • 2 cups of brown sugar


  • 2 eggs
  • 1 tsp of vanilla
  • 1/2 cup of milk

Mix in:

  • 2 cups of flour
  • 1 tsp of baking soda
  • pinch of salt
  • 4 cups of oatmeal
  • Add 1 pkg of chocolate chips

Bake at 350 F for 40 minutes.







One response to “Oatmeal Cookie Squares by Nana Haines”

  1. Bryan Sept 30 2022 Avatar
    Bryan Sept 30 2022

    3 sticks of butter
    1tbsp of psyllium housing powder
    11×13 pan
    Cooked 45 min @ 350 degrees
    3 eggs
    2tbsp of vanilla
    1tsp of cinnamon

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