These mini Brownie Sandwich Cookies make for a delicious and indulgent cookie treat! A sweet peanut butter frosting is sandwiched between two chewy brownie cookies. Serve them fresh or pack them up in the refrigerator to snack on cold – yes, they’re delicious cold! Whatever you do, you will love these!

Brownie Sandwich Cookies with Peanut Butter Frosting

Okay, you guys have been killing it with my Olive Oil Brownie Cookies – they’re hands down my most popular recipe over on Instagram and here on the blog! And I’ve loved seeing so many of your results from baking those cookies. So I decided to take the beloved brownie cookie up a notch by A) making them smaller and B) sandwiching them with an easy peanut butter frosting.

You guys. These cookies are so good. Eat them fresh while the frosting is nice and soft or pop them in your refrigerator to pop out and eat cold (my favorite way to eat them!). These cookies are so soft and chewy that even when cold, you can bite right into what tastes like brownie batter with a hint of sweet peanut butter. I couldn’t ask for a better chocolate snack, could you?

How to make Brownie Sandwich Cookies

These cookies are made just like my original Weeknight Brownies but with more flour to make the batter thick enough for cookies. The key to getting a consistent cookie across all of the batches is to allow the batter to sit at room temperature for around 30 minutes. This dries the batter out a bit, stiffening it up enough to scoop like regular cookie dough.

For the mini cookies, I found it easier to scoop the dough balls onto my parchment-lined baking sheet and then use my fingers to shape them while they’re on the sheet. Once all of the cookies are baked and cooled, you’ll whip up a simple buttercream frosting with plant-based butter, peanut butter, powdered sugar, and a little “milk”.

You can use a piping bag or ziploc bag fitted with a large, circular piping tip (or a star shape for a fancier look!) to pipe the frosting onto half of the cookies. Sandwich the cookies together and you’ve got a decadent little, peanut butter brownie treat! Yum!

Some of the ingredients + substitutions for this recipe:

Chocolate chips help give these cookies that crinkly, brownie-like top. I like to use a semi-sweet chocolate chip, but you can use dark or milk chocolate.

Vegetable oil adds tons of moisture to these cookies. I used olive oil in my cookies but avocado oil, melted coconut oil, or any kind of melted butter will work, too.

Instant Coffee (or espresso powder!) adds depth to the chocolate flavor. It’s totally optional, so don’t fret if you don’t have any.

Sugar sweetens these cookies, and I’ve successfully used coconut sugar, white granulated sugar, raw sugar, and brown sugar.

Dutch process cocoa powder adds a deeper chocolate flavor and color than regular, natural cocoa powder. You can use regular cocoa powder, but I recommend grabbing a box of the Dutched cocoa – it’s so good in many chocolate desserts!

Natural peanut butter is used to flavor the buttercream frosting. I’ve only used the natural kind (the only ingredient being peanuts) for this specific recipe. If you want to use a no-stir peanut butter with added oil, sugar, etc, you may need more or less milk or powdered sugar.

Yield: 15 Sandwich Cookies

Brownie Sandwich Cookies with Peanut Butter Frosting

Name: Brownie Sandwich Cookies with Peanut Butter Frosting
Prep time: 1 h
Cook time: 40 min
Total time: 2 h
Yield: 15
Cuisine: American
Ingredients: 1 cup dairy-free chocolate chips; 1/3 cup vegetable oil (I used olive oil); 1 tsp instant coffee granules (optional); 2 large eggs, room temp; 3/4 cup sugar (coconut or cane); 1 tsp vanilla extract; 1/4 cup Dutch process cocoa powder; 3/4 cup + 2 Tbsp all-purpose flour; 1/2 tsp baking powder; 1/2 tsp salt; 3 Tbsp plant-based butter, softened; 3 Tbsp natural peanut butter, room temp; 1/4 tsp vanilla extract; 1 cup powdered sugar; 2-4 tsp plant-based milk

Mini brownie cookies sandwiched together with an easy peanut butter frosting! These chewy, little cookies are delicious as-is or pop them in the refrigerator for a cold chocolatey snack.

Prep Time 1 hour

Cook Time 40 minutes

Additional Time 20 minutes

Total Time 2 hours

Ingredients

Brownie Cookies

1 cup dairy-free chocolate chips
1/3 cup vegetable oil (I used olive oil)
1 tsp instant coffee granules (optional)
2 large eggs, room temp
3/4 cup sugar (coconut or cane)
1 tsp vanilla extract
1/4 cup Dutch process cocoa powder
3/4 cup + 2 Tbsp all-purpose flour
1/2 tsp baking powder
1/2 tsp salt

Peanut Butter Frosting

3 Tbsp plant-based butter, softened
3 Tbsp natural peanut butter, room temp
1/4 tsp vanilla extract
1 cup powdered sugar
2-4 tsp plant-based milk

Instructions

Make the cookies:

Bring your eggs to room temperature by placing them in a glass of warm water for around 10 minutes.
In a small, microwavable bowl, melt the chocolate chips along with the oil and instant coffee. Heat in 30 second intervals, stirring each time, until chips are melted and smooth; set aside.
In a stand mixer fitted with the whisk attachment, add the eggs and sugar. Whisk on medium-high until thick, fluffy, and light in color, about 5 minutes.
Meanwhile, in a medium bowl, sift the cocoa powder, flour, baking powder, and salt. Whisk until combined and uniform in color; set aside.
Once the egg/sugar mixture has fluffed up and thickened, whisk in the vanilla. Then add the melted chocolate mixture and gently fold it into the egg/sugar mixture until totally combined. Add the dry ingredients and mix until just combined.
The dough will be like a very sticky, thick brownie batter. Allow it to sit at room temperature, uncovered, for 30 minutes. This allows the batter to stiffen up a bit so you can scoop the dough balls.
Preheat your oven to 350°F and line two baking sheets with parchment paper. Scoop cookies, eight at a time, 1 Tbsp in size onto one baking sheet. Gently shape and smooth each dough ball (optional). The dough balls should spread/flatten a bit once they're scooped. If not, go ahead and use your fingers to gently flatten the tops of the dough balls.
Bake the cookies at 350°F for 5-7 minutes or until the centers no longer look wet. Let cool on the baking sheet for 2 minutes before carefully transferring to a cooling rack.
Meanwhile (or while the cookies are baking), use the room temperature baking sheet to prepare another batch of dough for the oven. Continue until all cookies are baked. Allow your cookies to cool completely before making the frosting.

Make the frosting + assemble:

In a medium bowl beat together the butter and peanut butter. Beat in the vanilla and powdered sugar. Finally, beat in the milk 1 tsp at a time until the frosting comes together and is thin enough to pipe but thick enough to hold its shape.
Add the frosting to a piping bag or large ziploc bag fitted with a large, circular piping tip. Pipe the frosting onto half of the cookies, holding the bag upright in the middle of the cookie and applying a steady pressure until the frosting nearly reaches the edge.
Sandwich the frosted cookies and plain cookies together, pressing gently until the frosting reaches the cookies' edges.
Enjoy right away or store cookies in an airtight container in the refrigerator and eat them chilled like I do!