Fudge Ripple Monster Cookie Bars
Monster cookie bars with the classic combination of peanut butter, oats, and M&Ms, plus a layer of fudge running through the center!
Please, pretty please, tell us that you’ve heard of monster cookies or monster bars. If not, let us introduce you to one of our favorite combination of ingredients that you’ll find in any cookie or bar…
The dough typically includes peanut butter, oats, and M&Ms, which makes them one of the most popular little treats you’ll lay your hands on. We've made some variations over the years – monster cookies yearssssss ago, then followed those up with monster cookie bars and peanut butter lover’s monster cookies.
When we saw this new version in Sally’s cookbook, with a layer of fudge running through the center, we HAD to make them!
The beauty of monster bars like these is that, even though they involve the extra step of a fudge center, they are incredibly straightforward to mix together and you can have them in the oven in no time. Plus, it’s highly likely that you have everything you need to make these sitting in your pantry already. Aren’t those a standby kind of recipes?!
Don’t get freaked out by the word fudge! It can be so finicky to make actual fudge, right? Not this filling – it’s incredibly straightforward. All you need is some sweetened condensed milk, chocolate chips, butter and vanilla, then just heat it until melted, and you’re done. Honestly, we could probably just sit and eat the fudge filling with a spoon.
While we will always and forever prefer peanut butter over alternatives, we did make these successfully with Sunbutter because of Joseph’s peanut allergy. So if you need to make a similar substitution, you shouldn’t have any issues. We didn’t make any other adjustments, and they came out just fine.
If you’ve yet to meet a cookie with peanut butter, oats or chocolate that you didn’t like, then you will go bananas for these fudge ripple monster cookie bars!
Four years ago: From-scratch Hostess Cupcakes
Five years ago: Peanut Butter Blondies
Six years ago: Cranberry White Chocolate Chip Cookies
Fudge Ripple Monster Cookie Bars
Yield: 16 bars Monster cookie bars with the classic combination of peanut butter, oats, and M&Ms, plus a layer of fudge running through the center!Monster Bars
- 1⅓ cups (166.67 g) all-purpose flour
- ⅔ cup (54 g) old-fashioned rolled oats
- ½ teaspoon (0.5 teaspoon) baking soda
- ½ cup (113.5 g) salted butter, at room temperature
- ½ cup (110 g) light brown sugar
- ¼ cup (50 g) granulated sugar
- ¾ cup (193.5 g) creamy peanut butter
- 1 egg
- 1 teaspoon vanilla extract
- ¾ cup (177.44 g) M&Ms
Fudge Ripple Filling
- 7 ounces (198.45 ml) sweetened condensed milk
- 1 tablespoon salted butter
- 1 cup (180 g) semisweet chocolate chips
- 1 teaspoon vanilla extract
- Preheat oven to 350 degrees F. Line the bottom and sides of an 8x8-inch baking pan with aluminum foil, leaving an overhang on all sides. Set aside.
- Make the Bars: In a large bowl, whisk together the flour, oats and baking soda.
- Using an electric mixer, beat the butter, brown sugar and granulated sugar on medium speed until light and fluffy, about 2 to 3 minutes. Add the peanut butter, egg, and vanilla one after the other, mixing well after each addition. Scrape down the sides of the bowl as needed. Reduce the mixer speed to low and gradually add the dry ingredients, mixing until just combined. Do not overmix.
- Press two-thirds of the dough evenly into the prepared baking pan. Stir the M&Ms into the remaining dough. Set aside while you make the fudge ripple filling.
- Make the Fudge Ripple Filling: In a small saucepan over low heat, combine the sweetened condensed milk, butter and chocolate chips. Stir until the chocolate chips are melted and the mixture is smooth. Remove from the heat and stir in the vanilla. Pour the fudge over the bottom layer of dough.
- Mold the remaining dough containing the M&Ms into flat pieces and layer on top of the fudge filling. You won't have enough dough to make one single layer, so some of the filling will be exposed.
- Bake for 25 minutes, or until the top is lightly browned. Allow to cool completely. Lift the foil out of the pan using the overhang on the sides and cut into bars. Store in an airtight container at room temperature or in the refrigerator for up to 1 week.
Notes
We substituted Sunbutter for the peanut butter in this recipe and it worked just fine. Nutritional values are based on one bar
- Yield: 16 bars
- Prep: 25 minutes
- Cook: 25 minutes
- Total: 50 minutes
Ingredients
Monster Bars
- 1⅓ cups ( 166.67 g ) all-purpose flour
- ⅔ cup ( 54 g ) old-fashioned rolled oats
- ½ teaspoon ( 0.5 teaspoon ) baking soda
- ½ cup ( 113.5 g ) salted butter, at room temperature
- ½ cup ( 110 g ) light brown sugar
- ¼ cup ( 50 g ) granulated sugar
- ¾ cup ( 193.5 g ) creamy peanut butter
- 1 egg
- 1 teaspoon vanilla extract
- ¾ cup ( 177.44 g ) M&Ms
Fudge Ripple Filling
- 7 ounces ( 198.45 ml ) sweetened condensed milk
- 1 tablespoon salted butter
- 1 cup ( 180 g ) semisweet chocolate chips
- 1 teaspoon vanilla extract
Method
- Preheat oven to 350 degrees F. Line the bottom and sides of an 8x8-inch baking pan with aluminum foil, leaving an overhang on all sides. Set aside.
- Make the Bars: In a large bowl, whisk together the flour, oats and baking soda.
- Using an electric mixer, beat the butter, brown sugar and granulated sugar on medium speed until light and fluffy, about 2 to 3 minutes. Add the peanut butter, egg, and vanilla one after the other, mixing well after each addition. Scrape down the sides of the bowl as needed. Reduce the mixer speed to low and gradually add the dry ingredients, mixing until just combined. Do not overmix.
- Press two-thirds of the dough evenly into the prepared baking pan. Stir the M&Ms into the remaining dough. Set aside while you make the fudge ripple filling.
- Make the Fudge Ripple Filling: In a small saucepan over low heat, combine the sweetened condensed milk, butter and chocolate chips. Stir until the chocolate chips are melted and the mixture is smooth. Remove from the heat and stir in the vanilla. Pour the fudge over the bottom layer of dough.
- Mold the remaining dough containing the M&Ms into flat pieces and layer on top of the fudge filling. You won't have enough dough to make one single layer, so some of the filling will be exposed.
- Bake for 25 minutes, or until the top is lightly browned. Allow to cool completely. Lift the foil out of the pan using the overhang on the sides and cut into bars. Store in an airtight container at room temperature or in the refrigerator for up to 1 week.
