Oatmeal Cookie Bars in an 8x8 Pan

Oatmeal cookie bars in an 8×8 pan use 1/2 cup of butter, 3/4 cup of sugar (mostly brown), 1 egg, 3/4 cup of flour and 1 1/2 cups of old-fashioned oats, plus raisins or chocolate chips, baked at 350°F for 22 to 28 minutes. You get the taste of a soft oatmeal cookie in thick, chewy squares, without scooping or baking in batches.

The dough is a normal oatmeal cookie dough pressed into the pan, so you can stir in whatever you like in your cookies.

Why This Recipe Fits an 8×8 Pan

A single batch of this dough pressed into an 8×8 pan sits about 3/4 inch deep and bakes into bars just over an inch tall: soft in the middle, golden at the edges. In a 9×13 the same dough would be thin and crisp. If you want a larger batch, double it for a 9×13 rather than stretching one batch.

Ingredients for 8×8 Oatmeal Cookie Bars

1/2 cup (1 stick) unsalted butter, softened
1/2 cup packed light brown sugar
1/4 cup granulated sugar
1 large egg
1 teaspoon vanilla extract
3/4 cup all-purpose flour
1/2 teaspoon baking soda
1/2 teaspoon ground cinnamon
1/4 teaspoon salt
1 1/2 cups old-fashioned rolled oats
3/4 cup raisins, chocolate chips or a mix

How to Make Oatmeal Cookie Bars in an 8×8 Pan

Heat the oven to 350°F. Line an 8×8 pan with parchment, leaving an overhang on two sides.
Cream the butter and sugars until fluffy, about 2 minutes. Beat in the egg and vanilla.
Add the dry ingredients. Mix in the flour, baking soda, cinnamon and salt on low, then stir in the oats and raisins or chips.

Press into the pan. Spread the dough evenly, pressing it into the corners with damp fingers or the back of a spoon.
Bake 22 to 28 minutes, until the edges are golden and the center looks set but still soft. It firms up as it cools.
Cool in the pan for at least 45 minutes, then lift out and cut into 16 squares.

Cook and Prep Times

Prep: 15 minutes
Bake: 22 to 28 minutes at 350°F
Cool: 45 minutes
Serves: 16 bars

Mix-In Ideas

Oatmeal raisin: 3/4 cup raisins plus 1/4 teaspoon nutmeg.
Oatmeal chocolate chip: 3/4 cup semisweet chips.
Cranberry white chocolate: 1/2 cup dried cranberries and 1/2 cup white chips.
Nutty: swap 1/4 cup of the mix-ins for chopped walnuts or pecans.

Changing the Pan Size

9×9 pan: same recipe, bake 20 to 25 minutes.
9×13 pan: double the recipe and bake 25 to 30 minutes.

Storage

Store the bars in an airtight container at room temperature for up to 5 days, or freeze for up to 3 months. Separate layers with parchment so they do not stick.

Frequently Asked Questions

Can I use quick oats?

Yes. Quick oats give a softer, more uniform bar. Use the same amount.

Why are my bars dry?

They were baked until the center looked fully done. Pull them when the middle still looks slightly underset; carryover heat finishes them.

For more bakes sized for the same pan, see our blondies for an 8×8 pan, apple crumble in an 8×8 pan and key lime bars in an 8×8 pan.

Oatmeal Cookie Bars in an 8×8 Pan