Chewy Oatmeal Cookie Bars — My Mom’s Ancient Recipe
The Cookie My Family Has Been Requesting for Decades
Chewy oatmeal cookie bars are my most requested cookie — and if you ask me what cookie I want you to make for me, this is it, every single time. The recipe comes from one of my mom’s ancient cookbooks, and I need to tell you the name of this cookbook because it is one of the funniest cookbook names I have ever heard in my life: Straight from the Horse’s Mouth. I do not understand that name. But I do understand these cookies, and they are spectacular. Salty and sweet, chewy in the middle, crunchy on the edges — they hit every note. This is a bar cookie that has been around in my family for decades, and it is never, ever going home with leftovers.
🍰 This one’s in my collection of desserts for a crowd — the ones that travel well and feed a lot of people.
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Watch me make these chewy oatmeal cookie bars from start to finish — or scroll down for the full printable recipe card.
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Chewy Oatmeal Cookie Bars
Start CookingIngredients
- ½ cup shortening Crisco recommended
- 1 cup brown sugar packed
- 1 large eggs
- 1 tsp vanilla
- 2 ½ tsp baking powder
- 1 tsp salt
- ¾ cup all purpose flour
- 1 ½ cups quick oats
- Optional add-ins: nuts, raisins, chocolate chips, white chocolate chips, coconut flakes, butterscotch chips, or peanut butter chips
Don’t Want to Plan? I Got You.Every Saturday I share a full week of dinners, sides, and a dessert — with the grocery list already done. Come grab this week’s Weekly Meal Plans!Equipment
Method Start Cooking
- Preheat oven to 350°F. Grease a 9×13 pan.
- In a large bowl, mix shortening and brown sugar until combined.
- Add egg and vanilla and mix well.
- Add baking powder, salt, and flour and stir until incorporated.
- Fold in quick oats. The batter will be very thick.
- Press the batter evenly into the prepared 9×13 pan.
- Bake for 20–25 minutes until golden brown.
- Allow to cool before cutting into bars.
Nutrition
Video
Notes
Four Weeks of Family-Friendly FoodWhen people gather, I cook. Four weeks of the dinners my crowd asks for — planned, tested, and shopped for. Come see what’s in the cookbook →Why These Chewy Oatmeal Cookie Bars Work
Let me tell you a little more about this recipe, because it deserves its own story. My mom had this cookbook — and I am telling you, it was ancient. The kind of cookbook where the pages are soft and the spine is held together by sheer determination. And the name? Straight from the Horse’s Mouth. I still don’t understand it. But every single recipe I have ever made from that book has been delicious, so I have decided the title is irrelevant.
YOU’RE NOT GOING TO BELIEVE THIS — I FOUND THE cookbook ON AMAZON!!!!!
These chewy oatmeal cookie bars are the recipe I come back to the most. They are simple — basic pantry ingredients, no chilling the dough, no rolling, no cutting with cookie cutters. You mix, you press into the pan, you bake. That’s it. And yet somehow they are the cookie that everyone asks me to bring to every gathering, every potluck, every church dinner, every single time.
The secret — and I will shout this from the rooftops — is the Crisco . I am a generic brand girl in almost every area of my life. Store brand oats? Absolutely. Store brand salt? Of course. But Crisco is the one place I will not budge. I genuinely believe it makes a difference in these bars. And yes, before you ask, I like it better than the butter-flavored version too. That is my hill. I will die on it.
Now, about the pan. I made these with both my Farberware metal 9x13 and my Pyrex glass 9x13 in the video, and they both work. But the metal pan is better. I don’t have a scientific explanation for this. I just know it to be true. The edges get crispier, the bottom bakes up perfectly, and the bars hold together better when you cut them. Trust me on this one.
The other thing I love about this recipe is how easily you can make it your own. The base — oatmeal, brown sugar, shortening, egg — is a perfect canvas. Throw in white chocolate chips and coconut flakes and you have something magical. Add chocolate chips and you have a crowd favorite. Butterscotch chips, peanut butter chips, raisins, chopped nuts — all good. But my absolute favorite version? Plain. Just the oatmeal and brown sugar, exactly as written. Sometimes the simplest version is the best one. If you want to read more about why the type of oat matters in baking, King Arthur Baking has a great piece on baking with oats that walks through the differences.
A Few Things That Make Chewy Oatmeal Cookie Bars Even Easier
- Use Crisco , not butter. The recipe is built around shortening, and the texture is not the same with butter. I know, I know — every cookie recipe on the internet wants you to use butter. Not this one. The shortening is what makes these chewy in the middle and crisp on the edges.
- Quick oats, not old fashioned. The recipe calls for quick oats specifically and there is a reason. Quick oats are rolled thinner and break down a little as they bake, which gives you that uniformly chewy texture. Old fashioned oats stay too whole and the bars come out toothier than they should be.
- Reach for the metal pan if you have one. Glass works, metal is better. The metal pan gives you crispier edges, a cleaner bottom, and bars that hold their shape when you cut them. If glass is all you have, you’ll still get great cookies — they just won’t be quite as crisp around the edges.
- Double the recipe. I double this every single time I make it because one pan is never enough for my crowd. The recipe as written makes a 9×13 — about 24 bars. Doubled in two pans, I get 48 bars, and they still disappear faster than I can pack them up to share.
- Add-ins are optional and totally up to you. White chocolate chips and coconut flakes is my favorite mix-in combo. Semi-sweet chocolate chips is the crowd-pleaser. Butterscotch chips, peanut butter chips, raisins, chopped nuts — all good. But honestly? The plain version is my favorite of all of them. The base is that good.
Chewy Oatmeal Cookie Bars FAQ — The Questions I Get Every Time
What temperature and how long do I bake chewy oatmeal cookie bars?
Bake at 350°F for 25 minutes. The edges should be golden brown and the center should look just set — a little soft is fine, the bars firm up as they cool. If you pull them when the center is still glossy or wobbly, they’ll be underbaked and gooey in the middle. If you wait until the center is fully firm in the oven, they’ll be overbaked and dry. Trust the 25 minutes and let them finish setting on the counter.
Can I use old fashioned oats instead of quick oats?
You can, but the texture will be different — the bars come out toothier and a little more hearty, less of that uniform chewy texture these bars are known for. If old fashioned is what you have on hand, pulse them in a food processor four or five times to break them down into a quick-oats consistency, and you’re good to go. Or just use quick oats like the recipe calls for and skip the extra step.
Can I substitute butter for the shortening?
You can, but I’d rather you didn’t. The texture is genuinely different — butter bars spread more, lose the chew, and end up closer to a regular cookie bar than the salty-sweet bite this recipe is known for. The shortening is doing real work here. If you absolutely must swap, use the same amount of softened butter and expect a thinner, crisper bar.
Can I make chewy oatmeal cookie bars ahead of time?
Absolutely — these are perfect for making ahead. Bake them, cool completely, cut into bars, and store in an airtight container at room temperature for up to 4 days. They actually get better on day two as the brown sugar settles in. For longer storage, wrap individual bars in plastic wrap and freeze in a zip-top bag for up to 3 months. Thaw at room temperature for an hour and they taste freshly baked.
What’s the best add-in for chewy oatmeal cookie bars?
For a crowd, semi-sweet chocolate chips win every time. For something a little more interesting, white chocolate chips plus coconut flakes is my personal favorite — the coconut toasts beautifully and the white chocolate gives you these little pockets of sweetness. Butterscotch chips are excellent. Peanut butter chips work. Raisins and chopped pecans are the old-school move. Or skip the add-ins entirely and let the brown sugar and oats do the work — that’s the version I love best.
Why are my chewy oatmeal cookie bars crumbly?
Usually one of two things: overbaking or the wrong oats. If the center looked fully set when you pulled them from the oven, they baked too long — pull at 25 minutes even if they look a little soft in the middle, they finish on the counter. If you used old fashioned oats without pulsing them first, the bigger oat pieces don’t bind as well and the bars fall apart when you cut them. Quick oats fix both issues.
How many bars does this recipe make and can I double it?
One 9×13 pan gives you about 24 bars, depending on how big you cut them. I always double the recipe and bake in two pans because for our family of seven, one pan is gone the same night. Doubling works beautifully — same temperature, same time, just two pans on the same rack if your oven fits them or one rack at a time if it doesn’t. Same recipe, twice the cookies, same happy crowd.
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Ingredients
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More Crowd Desserts That Never Come Home with Leftovers
- Nestle Toll House Chocolate Chip Cookie Bars — quick, easy, and gone in minutes at any gathering
- Simple Cherry Cheesecake Bars — creamy, dreamy, and one of the easiest desserts you’ll ever make for a crowd
- Eclair Squares — Kathy Petty’s No Bake Dessert for a Crowd — no baking required and it has been requested at every potluck I’ve taken it to
- Soft Chewy Molasses Cookies — warm, spiced, and chewy in the middle, no chilling and no leftovers
- Monster Cookies — gluten free with no flour at all, one bowl, and everything in them
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Chewy Oatmeal Cookie Bars — About Stephanie’s Recipes
Stephanie Longstreth is the home cook, mom, and storyteller behind StephanieCooksForACrowd.com. She cooks for a family of seven in Florida — five kids, two cats, and one husband who appreciates a good meal. Four of her children came home through adoption, and family stories are woven into everything she makes and shares. Find her crowd-friendly recipes, weekly meal plans, and real family life on TikTok, Instagram, YouTube, and Pinterest @stephaniecooksforacrowd.