These flourless Small-batch Monster Cookie Bars are easy to make and come out gooey, peanut buttery, and perfect every time.
Craving something sweet and peanut buttery but don’t have any flour in your cupboard? You should make a little batch of monster cookie bars…
Easy No-flour Cookie Bars
These small-batch monster cookie bars are a super simple one-bowl dessert that requires zero flour. They’re big on peanut butter flavor and packed full of M&Ms and melty chocolate chips.
Monster cookie bar recipes usually make an entire sheet pan of bars, but this small-batch recipe bakes in a loaf pan and makes just 6 to 8 cookie bars, which is probably good right now, because they are ridiculously addicting, and however many you make is probably how many you will eat. 😉
What is their texture like? The texture of monster cookie bars is somewhere between a cookie and a (good) granola bar. Since there’s no flour, they’re not pillowy like a soft cookie.
Instead, they’re a little gooey and chewy, with a bit of crispiness around the outer edges and lots of texture from the oats.
A Note on Oats
I called for quick-cook oats in this recipe (AKA instant or minute oats) because these oats have been processed into smaller pieces for quicker cooking, and I prefer their texture in baked goods.
But you can use old-fashioned/rolled oats if that’s what you have on hand. The oat texture will just be slightly more aggressive.
You cannot use steel-cut oats in this recipe.
Notes & Substitutions
- I don’t have a loaf pan: If you don’t have a standard-size 1-pound loaf pan, you can use a 5×7-inch baking dish, just extend the baking time slightly since your bars will be a bit thicker.
- I don’t have M&M’s: The texture the crunchy candy shells add to these bars is really fantastic, so if you can get M&M’s, I recommend using them, but any baking chip (I bet peanut butter chips would be stellar) or chopped chocolate candy will work here as a substitution.
- I don’t have oatmeal: Sorry, friend, you cannot substitute for or omit the oatmeal in these bars. If you don’t have oatmeal, give my Small-batch Peanut Butter Cookies a go. You can add 1/2 cup of M&Ms or chocolate chips and still get that chocolate and PB fix, no oatmeal required.
- These bars need about 45 minutes to cool and firm up, otherwise they will fall apart when you try to cut and eat them. BUT if you really want to eat them warm and melty, scoop a serving into a bowl, add a scoop of ice cream and Fudge Sauce or Peanut Butter Sauce, maybe top with a little Whipped Cream and make a sundae out of it!
More Small-batch Recipes
Small-batch Monster Cookie Bars
- 1-pound loaf pan
- 3 tablespoons (42g) salted butter softened*
- 1/2 cup (132g) peanut butter creamy or chunky*
- 1/3 cup (67g) granulated sugar
- 1/3 cup (67g) brown sugar
- 1 large egg
- 1/2 teaspoon vanilla extract
- 1 1/2 cups (130g) quick/instant oats *
- 1/2 teaspoon baking soda
- 1/2 cup (85g) M&M’s plus more for topping
- 1/3 cup (56g) chocolate chips
- Preheat your oven to 350°F. Lightly grease and line a loaf pan with parchment paper.
- In a medium bowl, combine softened butter, peanut butter, and granulated and brown sugars. Beat until well-combined and slightly lightened in color, about 1 minute.
- Add egg and vanilla and mix until well-combined.
- Add oats and sprinkle baking soda over the top. Mix until well combined.
- Add M&M’s and chocolate chips and use a wooden spoon or spatula to mix.
- Transfer mixture to prepared baking pan and press dough out into an even layer. Sprinkle a few extra M&M’s over the top if desired, and bake for 15 to 18 minutes, until the edges are lightly browned (the center will still look pale and slightly underdone). Do not overbake!
- Allow bars to cool in the pan for about 45 minutes so they can firm up before transferring to a cutting board and slicing.
- Serve and enjoy!
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