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Oh for the love of all things gooey: Oatmeal Cookie S’mores Bars are here! These are oatmeal cookie bars full of marshmallows and chocolate. The EPIC indoor s’more recipe!

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Overhead shot of oatmeal cookie s'mores bars cut into squares

Indoor S’mores: Oatmeal S’mores Bars

We love s’mores no matter what vehicle they come in. Parfaits, with cookies, blondies, in pie…she loves s’mores in every form. Who doesn’t?

(My husband doesn’t. He doesn’t like marshmallows. !!!! I love him anyway.)

We all know that I’m an indoor s’more person. Hand me a blowtorch and a marshmallow on a skewer and I’ll go to town. Make me sit outside and make s’mores? Not going to happen.

So I think I’m making it my goal in life to make alllll things indoor s’more. Frozen pie? Got it. No bake bars? Yup. Blossom Cookies? Check!

And now? We can add Oatmeal Cookie S’mores Bars to the list. I took oatmeal cookie bars and turned them into gooey s’mores bars.

That was a realllly good decision.

Overhead shot of oatmeal cookie s'mores bars cut into squares

Why This Recipe Works

This recipe is super easy, as usual. I decided to adapt my Dulce de Leche Revel Bar recipe into these s’mores bars. The base of the cookie is pretty much the same as my normal oatmeal cookie recipe except it uses a full cup of brown sugar.

Brown sugar is GOOD.

Overhead shot of six images showing the process of making oatmeal s'mores cookie bars
  1. Mix together your butter and sugar until it’s nice and creamed.
  2. Add the eggs, vanilla and dry ingredients and mix until smooth.
  3. Press half of it into a 9×9″ pan. Be sure to line it with parchment or foil and spray it well with cooking spray: marshmallows get sticky after they’ve baked!
  4. On top of the bottom cookie dough layer, you spread marshmallow creme. (Also known as “fluff” depending on the brand you buy.) I heated my marshmallow creme in the microwave for just a few seconds to thin it out a little, which makes it easier to spread over the dough.
  5. Then you sprinkle chocolate chips all over it.
  6. Then top it with the rest of the cookie dough.
Hand holding one square of oatmeal cookie s'mores bar close to camera

You’ll bake these about 28-35 minutes or until they’re just a bit jiggly and light golden brown around the edges.

Storing and Freezing Instructions

Store these in an airtight container for up to 4 days or freeze them for up to 3 months. Learn how I freeze all desserts!

Overhead shot of oatmeal cookie s'mores bars cut into squares

Expert Tips

  • When you’re spreading the marshmallow, make sure and leave a thin marshmallow-free zone around the edge of the pan. Unlike regular marshmallows, marshmallow fluff does not disappear when you bake it. It’s like magic!
  • When you drop the rest of the cookie dough on top, make sure it seals around the edges. It’ll keep the marshmallow inside the bars.
  • Want to use other kinds of chocolate chips, like white chocolate or butterscotch? Feel free to substitute!

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Bunch of Oatmeal Cookie S'mores Bars
5 from 6 votes
These Oatmeal Cookie S’mores Bars are over the top gooey bars! Oatmeal cookie dough is filled with marshmallow cream and loads of chocolate for the most decadent s’more ever!
Prep Time 20 minutes
Cook Time 30 minutes
Total Time 50 minutes
Yield 16 bars
Serving Size 1 bar


  • ½ cup (113g) unsalted butter softened
  • 1 cup (200g) brown sugar packed
  • 1 large egg
  • 1 teaspoon vanilla extract
  • ½ teaspoon baking soda
  • ½ teaspoon salt
  • 1 ¼ cups (155g) all purpose flour
  • 1 ½ cups (128g) quick cooking oats
  • 1 7 ounce jar marshmallow creme
  • 1 cup (170g) chocolate chips milk or semi-sweet
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  • Preheat oven to 350°F. Line a 9×9” square pan with foil and spray well with cooking spray. You can use parchment in place of foil, if you prefer.
  • Cream butter and sugar in a mixer fitted with the paddle attachment. Cream until smooth, just a minute or so. Beat in egg, vanilla, baking soda, and salt. Mix in flour then slowly mix in oats.
  • Press half the mixture into the bottom of the prepared pan. It will be a thin layer. The dough is sticky so I suggest spraying your hands with cooking spray to help the dough not stick to you.
  • Take the lid and foil wrap off the jar of marshmallow creme. Microwave it for just a few seconds (10-20 seconds) watching it carefully – take it out just as it starts growing up out of the jar. Pour over the bottom layer in the pan and spread evenly, being careful to leave a border around the edge with no marshmallow. Sprinkle with chocolate chips.
  • Use two spoons to scoop the remaining dough. Flatten scoops with your hands and layer over the top of the bars, trying to be sure and cover all the edges with dough.
  • Bake for about 23-28 minutes, until the top of the bars are golden brown. The pan will still be slightly jiggly. Let them cool completely before attempting to slice. They’ll be gooey! Store in an airtight container for up to 4 days.

Recipe Nutrition

Serving: 1bar | Calories: 228kcal | Carbohydrates: 34g | Protein: 3g | Fat: 9g | Saturated Fat: 5g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 2g | Trans Fat: 1g | Cholesterol: 27mg | Sodium: 123mg | Potassium: 61mg | Fiber: 1g | Sugar: 21g | Vitamin A: 217IU | Vitamin C: 1mg | Calcium: 33mg | Iron: 1mg
Nutritional information not guaranteed to be accurate
Course Dessert
Cuisine American

Sweets from friends:
Peanut Butter S’mores Bars by The Food Charlatan
Soft and Gooey Loaded S’mores Bars by Averie Cooks
S’mores Magic Bars by Wine & Glue

Oatmeal cookie s'mores bars cut into squares with recipe title on top of image

If you’re looking for all things gooey – look no further! These Oatmeal Cookie S’mores Bars are an Oatmeal cookie filled with marshmallow cream and loads of chocolate for the most decadent s’more ever!SaveSaveSaveSaveSaveSave

Last Updated on May 16, 2022

Dorothy Kern

Welcome to Crazy for Crust, where I share recipes that are sometimes crazy, often with a crust, and always served with a slice of life.

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  1. Hi there! I see that you used a jar of marshmallow creme I have regular marshmallows would the recipe turn out if I dont Use marshmallow creme?

    1. Yes you can make it into a cookie – I’m not sure if the dough needs chilling or not, so try baking just a few to see if they flatten too much or okay for your liking.Just be sure that you put the creme inside two balls of dough and completely seal it – if it gets out at all it’ll melt all over.