These Monster Cookies have a marshmallow fluff base instead of peanut butter, and are jam packed with candies. A soft and chewy cookie with a crispy bite.
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Monster Cookies – Marshmallow Fluff Based!
Don’t you just hate it when you’re gearing up to make/bake something and you know that you have the ingredients in. Then comes the time where you put your thoughts and efforts into action only to find that 1 or more of the ingredients you knew you had in.. well, isn’t in!
I knew for a fact we had crunchy peanut butter in. Not only 1, but I knew there were 2 jars of it. The giant man-baby doesn’t like PB so I’m guessing it met its death by him. I also knew I replenished the bicarbonate of soda (baking soda) too. And I knew that when I last ran out of it, that I went a little crazy and bought something stupid like 5 packages of the stuff. Know, know, KNOW!!!
So, where the devil are they? By this point I had already mixed half of the ingredients together and the oven was preheated – there was no backing out now! Bicarb of soda is pretty darn important in this cookie recipe, but it was already 11pm and I was in my PJ’s (and apron, sexy!), so I was going to substitute for baking powder. That was nowhere to be seen neither. Gah! I had to use self-raising flour since all that contains is plain/all purpose flour with baking power added.
As for the peanut butter, what could I substitute that for? I opened my pantry cupboard and there it was staring right back at me. The little Devil voice in my head was saying “Ooo, pick me.. pick me”. The Marshmallow Fluff was the answer to those prayers! And ¾ of the entire jar. Oh, yes!
So these bad boys are just that. I wrongly described them on Twitter as ‘heavenly’, but devilish is more appropriate with all those different candies in these puppies…
There’s…
- Marshmallow fluff
- Shaved milk chocolate
- Munchies candy (which are milk chocolate-coated candy with a caramel and biscuit centre)
- Chocolate M&M’s
- Smarties (which are pretty much the same as M&M’s but slightly larger and flatter)
- Chopped Rolo’s
Badddddd! You ought to have seen the caramel leaking out and bubbling from the cookies as they were baking. I couldn’t wait the whole 12 minutes they took to cook.
Over all, they’re deliciously sweet and have a wonderful chewy inner with a slightly crispy outer. And everyone in my house is raving how yummy they are. My kids don’t even like oatmeal!
I’ve included my recipe below for these exact cookies. For the candy, I have called for ¾ of a cup but being honest, I eyeballed all of the candy used. Most of the candies I used were in small 113-200g bags and used all from the bags.
Also, for anyone wanting to replicate this outside of the UK, Smarties can be substituted for Reese’s pieces, Munchies can be substituted for roughly chopped Twix bars (1x two finger bar should be sufficient).

Marshmallow Fluff Monster Cookies
Yield: 26 large cookies
Prep Time: 15 minutes
Cook Time: 10 minutes
A marshmallow fluff (instead of peanut butter) based soft cookie, jam packed with candies; M&M's, Rolo's, Munchies, and Smarties candy bars.
Ingredients:
- 3 large eggs
- 1 cup granulated sugar
- 1 cup light brown sugar
- 1 tsp vanilla extract
- 1 tsp golden syrup (or light corn syrup)
- 2 tsp bicarbonate of soda (baking soda)
- 1 tsp salt
- ½ cup butter, melted
- ¾ jar Marshmallow Fluff
- 4½ cups rolled oats
- ½ cup plain/all purpose flour
- ¾ cup milk chocolate, shaved
- ¾ cup Munchies candy
- ¾ cup chocolate M&M’s
- ¾ cup Smarties candy
- ½ cup Rolo’s, roughly chopped
Directions:
- Line 2 baking trays with parchment paper or a silicone baking mats. I got to use my brand spanking new Silpats!
- Using an electric mixer, mix together the eggs, granulated and light brown sugars, vanilla extract, golden syrup (or light corn syrup), bicarbonate of soda (baking soda), and salt.
- Next, add in the melted butter, marshmallow fluff, followed by the oats and plain/all purpose flour. Mix until combined.
- Finally, gently fold in the shaved chocolate, munchies, chocolate M&M’s, smarties and chopped rolo’s. I leave this until last as I don’t want my mixer breaking up all the sugar shells on the M&M’s and Smarties. Leave the dough to rest for 30 mins. Meanwhile, preheat your oven to 180°C, 350°F, Gas Mark 4.
- Using a cookie scoop, scoop even sized balls onto the baking sheets allowing enough room between dough for spreading during baking. Slightly flatten the balls with your fingers.
- Bake for 10-12 minutes, or until the cookies are a light golden brown colour. Allow to cool on the parchment paper on a wire rack until they harden enough to handle. Store in an airtight container. No need to refrigerate.
If you give these a try, do let me know if you like them.

Way to improvise, Lisa! I would have freaked. out. seeing as I am constantly forgetting stuff until I’m cooking and need it rightthisverysecond and then proceed to freak out some more. The marshmallow fluff sounds super good!! However, I had to admit, I had a brief moment of panic when I saw Smarties on the list of ingredients–in the US we have a candy called Smarties but they’re like this weird chalky candy that tastes vaguely like fruit and I thought, is she really baking with those chalky Smarties candies?! until I realized your version is like M&M’s which is awesome. Believe me, US Smarties aren’t as cool haha.
OOOOooooooooh!
Marshmallow fluff???? IN YOUR COOKIES? Your, m’dear, are a frickin’ genius.
Seriously!!?!!! I would have just sat down under my kitchen table and cried because I didn’t have what I needed ! Way to be creative! And they look amazing, I’m sure they taste fabulous!!
I’m meant to be eating healthy this week…. but these look pretty tasty…
So many wonderful candies going on in these perfect cookies. Monster cookies re my favorite b/c I love a lot of chunks and textures in my cookies!
Love the sound of this variation to monster cookies! Great idea to try marshmallow fluff!
Love the sound of this variation to monster cookies! Great idea to try marshmallow fluff!
Yep! At times 12 minutes can be pretty long! Good then, that others still had the chance to taste them!
holy moley… can i be cookie monster for a day & devour a whole batch of these treasures!?
xo
http://allykayler.blogspot.ca/
holy moley… can i be cookie monster for a day & devour a whole batch of these treasures!?
xo
http://allykayler.blogspot.ca/
Wow! This cookies are insane! Also Munchies candy, never hear of it, but it sounds amazing. Where can I get my hands on some?
Wow! This cookies are insane! Also Munchies candy, never hear of it, but it sounds amazing. Where can I get my hands on some?
Love your improvisation my friend, these cookies look sooooo delish!
Cheers
Choc Chip Uru
Love your improvisation my friend, these cookies look sooooo delish!
Cheers
Choc Chip Uru
Love these! I hadn’t given much thought about the possibilities as much as I should be, obviously! Yum!! I hope to figure something out like these!
Love these! I hadn’t given much thought about the possibilities as much as I should be, obviously! Yum!! I hope to figure something out like these!
I’d love to try one of your monster cookies right about NOW! 🙂
I’d love to try one of your monster cookies right about NOW! 🙂
Wow, this version of Monster cookies sound wonderful! Will have to add this to my monster cookie collection!
these munchies sound good 🙂
these munchies sound good 🙂
YUm YUM! Loks super delicious! I love oatmeal cookies:-) I would love you to jin My Sweet party! The theme for August is childhood favourites.
http://meandmysweets.blogspot.se/2012/08/my-sweet-party-august-childhood.html
Cheers!
YUm YUM! Loks super delicious! I love oatmeal cookies:-) I would love you to jin My Sweet party! The theme for August is childhood favourites.
http://meandmysweets.blogspot.se/2012/08/my-sweet-party-august-childhood.html
Cheers!
Sorry! I just realised that you already posted those amazing moster cookies! 🙂
Sorry! I just realised that you already posted those amazing moster cookies! 🙂
Wow, these sound really fantastic!! I can’t even count the number of last minute trips to the grocery store I have made, with cookie dough half-mixed in my mixer. It’s SO frustrating! I feel your pain!
Wow, these sound really fantastic!! I can’t even count the number of last minute trips to the grocery store I have made, with cookie dough half-mixed in my mixer. It’s SO frustrating! I feel your pain!
Umm, wow. These looks insane and I mean that in the best possible way, you especially had me with the fluff. I try to bake every weekend, so I know whats on my shopping list!!
Umm, wow. These looks insane and I mean that in the best possible way, you especially had me with the fluff. I try to bake every weekend, so I know whats on my shopping list!!
Omggggg…so much candy and chocolate in a single cookie has got to be sinfully delicious. I kmo what type of cookie i am making next 😉
Wow, these cookies look so YUMMY! I will be making these, thanks for sharing!
Wow, these cookies look so YUMMY! I will be making these, thanks for sharing!
Ooo I LOVE that these aren’t the traditional peanut butter monster cookies! And I’m a sucker for marshmallow fluff… that stuff is amazing. And haha omygoodness- so much candy! These cookies are dangerous Lisa! YUM!
Ooo I LOVE that these aren’t the traditional peanut butter monster cookies! And I’m a sucker for marshmallow fluff… that stuff is amazing. And haha omygoodness- so much candy! These cookies are dangerous Lisa! YUM!
Wow, these cookies look so YUMMY! I will be making these, thanks for sharing!
Wow, these cookies look so YUMMY! I will be making these, thanks for sharing!