I can say with absolute confidence that this Brownie Cookie Sandwich is the most indulgent cookie I have ever had in my life. And boy am I glad that it came out of my kitchen. Imagine if I had this at a fancy patisserie? They’d never share the recipe with me – that would be tragic!
It tastes like a brownie, in cookie form – PLUS peanut butter frosting!
I don’t bake much because I am more of a savoury person than a sweet person. So most sweet things I make are “fast and easy” type treats.
But this….this is worth every second of effort. It is crazy indulgent and ridiculously scrumptious. The brownie cookie is just like a brownie in both texture and taste. The surface of the cookie has the familiar thin crinkly layer. On the brownie scale of super dense and fudgey through to cakey, this cookie lies somewhere in between. The inside is soft and moist and every so slightly chewy. And it’s really, really chocolatey.
The frosting is delightful. It is so fluffy and creamy with a distinct peanut butter flavour. It is sweet but also has a touch of salt which a key element of the flavouring that makes the frosting so insanely addictive.
So put the brownie cookie and peanut butter frosting together and you have perfection in a cookie.
The idea for this cookie sandwich came from a recipe by Donna Hay (an Australia celebrity cook) but I used a brownie cookie recipe by Jen’s Favorite Cookies and a Peanut Butter Frosting by Ina Garten (aka Barefoot Contessa), from her cookbook “Barefoot Contessa at Home: Everyday Recipes You’ll Make Over and Over Again“.
The brownie cookie recipe is in US measurements but I was confident it would work using Australia cups and teaspoons (which are slightly different) because this is a “low risk” baking recipe. I guessed right, it worked brilliantly. I’ve made it twice now and both times it came out exactly the same.
The cookies you see in the photos are giant size – they are just a touch larger than the size of my palm (but mind you, I have abnormally small Baby Hands). They are around 3.5″/8.5cm in diameter. I made them gigantic because my irrational logic told me that was a smart move, instead of dealing with the guilt of having two normal sized cookie sandwiches. But if you are a normal person, by all means make them normal size. I’ve provided directions for both below. 🙂
– Nagi
All things Brownies
-
Outrageous Nutella Brownies – lives up to their name!
-
Gluten Free Brownies – so moist, with a hint of almond flavour
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Brownie Cookie Sandwich with Peanut Butter Frosting
Ingredients
Brownie Cookie
- 1 stick / 1/2 cup / 115g unsalted butter , cut into chunks
- 10 oz / 300g dark chocolate chips (or buttons, melts or block chocolate cut into chunks)
- 1 cup + 2 tbsp caster sugar
- 3 eggs
- 2 tbsp cocoa powder
- 1 tsp vanilla extract
- 1/2 tsp salt
- 1/2 tsp baking powder
- 3/4 cup plain flour
- 1/2 cup dark chocolate chips
Peanut Butter Frosting
- 1 cup smooth peanut butter
- 1 cup confectioners' sugar (icing sugar)
- 2.5 oz / 5 tbsp / 70g / 2/3 stick unsalted butter , softened
- 3/4 tsp vanilla extract
- 1/4 tsp salt
- 1/3 cup heavy cream (unwhipped pouring cream)
Instructions
Brownie Cookie
- Preheat oven to 180C/350F.
- Line two baking trays with parchment / baking paper.
- Pour 1" / 2.5cm of water into a large saucepan or small pot and bring to a simmer over medium low heat.
- Place a bowl over the simmer water and melt the butter and 10oz/300g chocolate chips. Stir until smooth.
- While the chocolate is melting, place the eggs, cocoa powder and sugar in a bowl and beat for 3 minutes on high (using an electric beater or stand mixer with the whisk attachment).
- Pour 1/3 of the melted chocolate into the egg mixture and mix well, then pour the remaining melted chocolate in and mix again.
- Add the vanilla, salt and baking powder and mix until combined.
- Add the flour and mix until just combined - do not over mix.
- Fold in 1/2 cup dark chocolate chips. See image below for batter consistency.
- To make large ones like I did, drop 2 tbsp of mixture onto the baking tray, leaving 2"/5cm between each cookie. To make normal sized ones, use 1 tbsp of mixture per cookie. (Note 1)
- Bake large cookies for 15 minutes for very soft or 17 to 20 minutes for firmer cookies. Bake small ones for 10 to 12 minutes for very soft, or 15 minutes for firmer. (Either way it is still moist!)
- Allow to rest on the baking tray for 5 to 10 minutes before carefully transferring to a cooling rack.
Peanut Butter Frosting
- Place all ingredients except the cream in a stand mixer bowl with the paddle attachment. Beat for 5 minutes on high, or until creamy. Scrape down the sides as you go. Add the cream then beat for a further 2 minutes, or until the frosting is fluffy.
- This can also be done using a hand held beater but it will take a few minutes longer.
Assemble
- Spread Peanut Butter frosting on a cookie, then sandwich with another cookie. Repeat with remaining cookies.
Recipe Notes:


Nutrition Information:
I had the same issues as others. Although these did taste great, I found the batter really runny and had to add extra flour. Also, the buttercream was so soft that we couldn’t sandwich them together because it all squeezed out.. We just spread it on one half and ate them individually.
Good, but buttercream just squishes out when bitten into. Might do a layer of ganache instead next time.
I made these the other day and they were amazing! Super easy to make and everyone loved them!
When you say castor sugar in the cookie batter is that the same as confectioners sugar? Just wanted to clarify since I’ve never heard of using confectioners sugar in cookies.
Hi Nagi, do you think this peanut butter frosting would work on your chocolate cupcakes?
Yes 100%! I love this idea Lyn! N x
I made your chocolate cupcakes with this peanut butter frosting today Nagi & they were insanely good!!
Hi Nagi
The batter whilst delicious and moist came out a bit runny despite adding the said amount of flour (3/4 cup) as stated in the recipe .
I did add a bit more flour though the batter still doesn’t seem very firm
Wondering where I went wrong .
Baking a second batch and will probably add more flour to it
Hi Nagi!
Just wondering if your tablespoons are 15mL or 20mL? I’ve noticed that US tablespoons are 15mL and Aussie ones are 20mL but thought I’d double check with you.
Cheers.
Hi Nagi!
What conversion should i use if i want to convert the cups over to grams?
Thank you:)
Apologies Nicole, I usually have both grams/cups listed – I’ll update for you! N x
How goes the conversion Nagi? I live in Japan so grams would be wonderful!
Thanks Nagi!
Looking forward to hearing from you(:
Hi Nagi,
We have 2 types of cream one is the whipping cream which is sweet in liquid form & one is the normal not sweet heavy cream which doesn’t really whip up very well.
Which is the better option?
Thanks
Hi your recipe says unsalted butter as well as salt could you use salted butter instead of the unsalted butter and added salt
I made these and although they tasted amazing they were super thin. Any idea why? Baked them for 10 mins and it was burnt, ended up baking them for 5mins and 30 seconds.
Hi Susan, yes I always prefer to use unsalted butter than I can adjust the salt to suit. You can use salted butter if you prefer, just omit the salt in the recipe – N x
Fantastic recipe. Very straight forward. Super decadent.
I’m so glad you loved it Robert!
I loved the idea of this recipe but I failed so terribly for me :’(
I switched out dark chocolate for white chocolate…..
They spread into one giant slab…..what did I do wrong? This is my first baking fail and I’m so disappointed 🙁
Hi Kimberley, white chocolate reacts differently to milk/dark chocolate, so that would have been the problem here unfortunately – N x
I made these yesterday and they are AMAZING!!!! Thanks for sharing!!!!
You’re so welcome Amy!!
Nagi!
You are going to get sick of me commenting haha
I work at an Ambulance Station and this morning I made these cookies, the brown sugar apple muffins and the Hasselback French toast for a bit of a feast for the crew and all I can say is WOW WOW WOW. All three of these were an absolute HIT 🙂
So glad to have found your website. EVERYTHING is so delisious!!!!!
I love brownie so much! Thank you for this recipe and I’ll it this weekend
I’m so glad you enjoyed it Mai, thank you for letting me know! N x
Do I use a paddle or whisk attachment if I use my stand mixer to make this?
Hi Stephanie! I use the whisk attachment for the batter then the paddle attachment for the frosting. Just updated the recipe 🙂
Could I use brownie mix to make the bRonnie cookies ? Thanks in advance.
I’m not sure sorry Adam, I’ve never made this with a brownie mix
These are amazing!! I only used half the icing. And it was easier to scoop out the dough if you cooled it a bit first. I used a small cookie dough scoop (about a tbsp) and got 2 dozen generously sized cookies.
WOO HOO! So glad you loved it Brittany, thank you SO MUCH for taking the time to let me know!! N x❤️
Ooh, these look great! I’ve made the Donna Hay version before and it was yummy! I love Ina Garten’s recipes too, I bet her peanut butter frosting would be awesome 🙂
Barefoot Contessa is the BEST!! N x
Hi Nagi, could you suggest something that i could use to replace the eggs with? I am a vegetarian!
Oh Meeta! I’m afraid I don’t know enough about the science of baking to suggest a replacement. I’m sorry! I can, however, refer you to my friend’s blog who has a fantastic collection of eggless baking recipes!! Here it is: http://priyakitchenette.com (PS the brownies are sensational!)