I wasn’t even craving cookies. That’s the weird part. I was cleaning up the kitchen, half listening to the news, half wondering why I always forget to buy more parchment paper, when my brain suddenly went, remember cosmic brownies?
Like… out of nowhere.

You know those old-school Cosmic Brownies. The shiny chocolate top. The slightly fake-tasting rainbow chips. The way they somehow felt special even though they came out of a box. I hadn’t thought about them in years. And suddenly that memory just parked itself in my head and refused to leave.

So naturally, instead of doing anything productive, I started thinking: What if that flavor was a cookie? Not a perfect copy. Not a gimmick. Just… a cookie that feels like a cosmic brownie grew up a little.

That’s how these Cosmic Brownie Cookies happened. Not planned. Not tested a million times. Just one of those “let’s see what happens” baking days.

Why these Cosmic Brownie Cookies work (even though I wasn’t 100% sure they would)

I’ll be honest — I wasn’t convinced at first. Brownie cookies can go wrong fast. Too dry. Too cakey. Too flat. Too sweet. Too much cocoa. Not enough cocoa. It’s a fine line.

But these? They landed right in that sweet spot. Soft centers. Set edges. Deep chocolate flavor that doesn’t punch you in the face. And then the ganache on top — glossy, smooth, a little dramatic — with those rainbow candies that make everything feel nostalgic again.

They don’t taste exactly like the boxed brownie. And I’m glad. These Cosmic Brownie Cookies feel richer, less sugary, and a little more intentional… but still playful. Still fun. Still the kind of thing you’d absolutely sneak off the cooling rack when no one’s looking.

Ingredient thoughts (not rules, just thoughts)

I don’t love overexplaining ingredients, but a few things matter here.

• Brown sugar is non-negotiable. That chewiness? That’s the brown sugar doing the heavy lifting.
• Cocoa powder — Dutch-processed if you have it. Regular works too. I’ve used both. Some days I honestly can’t tell the difference.
• Butter should be soft. Not melted. If it’s a little too soft because you forgot it on the counter (been there), it’ll still work. Just know the cookies may spread more. Not a disaster.
• Ganache is just cream and chocolate, but timing matters. Too hot and it’s runny. Too cool and it’s stiff. There’s a sweet spot, and you’ll feel it when you hit it.

And the rainbow chips? Use a lot. Or a little. Or whatever’s left in the pantry. I’m not the sprinkle police.

How the cookies come together (real-time energy, not perfection)

1. You cream the butter and sugar first. Give it a minute. Let it get fluffy. If it doesn’t look perfect? Keep going. It usually gets there.
2. Add the egg and vanilla. The batter will look glossy and kind of thick — almost brownie-like already. That’s a good sign.
3. Once the dry ingredients go in, stop mixing as soon as everything comes together. Overmixing is where good intentions go to die. The dough should be soft but scoopable. If it feels sticky, that’s normal.
4. Bake them until the edges look set but the centers still look a little unsure of themselves. That’s exactly where you want them. They’ll firm up as they cool. If you wait until they look fully done in the oven, they’ll be dry later. Ask me how I know.
5. And then… you wait. I hate that part. But warm cookies and ganache don’t mix unless you’re into chaos baking.

The ganache moment (aka my favorite part)

1. This is the part where everything suddenly feels fancy.
2. Heat the cream until it’s hot but not boiling. Add the chocolate. Walk away for a minute. Come back and stir. It turns glossy and smooth and honestly kind of hypnotic.
3. Spread it gently over each cookie. Don’t rush it. Sprinkle the rainbow chips while the ganache is still soft so they stick. Then let it set.
4. At this point, they really do look like Cosmic Brownie Cookies. And every single time, that still makes me smile a little.

Storage (if you’re stronger than I am)

Once the ganache sets, these cookies keep well at room temperature for a day or two. If your kitchen is warm, pop them in the fridge — just let them sit out for a few minutes before eating so the ganache softens again.

They freeze beautifully without the ganache. Which is both useful and slightly dangerous information.

Little tweaks I’ve tried (and didn’t hate)

• A pinch of espresso powder in the dough = deeper chocolate flavor.
• Dark chocolate chips in the ganache = less sweet, more grown-up.
• Extra rainbow candies because… why not?

Some batches are better than others. Some days I like them thicker. Some days thinner. That’s baking. That’s life.

What I eat them with

Milk is classic. Coffee is better. Standing at the counter, eating one slightly too early, is best.

FAQ:

Do these actually taste like cosmic brownies?
They feel like them. The vibe is there. But they’re richer and less sugary. I prefer them this way… most days.

Can I make them ahead?
Yes. Bake first. Ganache later. Easy.

Why didn’t mine look perfect?
Mine don’t always either. They’re cookies, not jewelry.

If you’re craving something chocolatey, nostalgic, and just a little fun, these Cosmic Brownie Cookies are worth your time. Even if you’re not totally sure when you start. Especially then.

If you make them — honestly — tell me how it went. Did they spread too much? Did you add extra sprinkles? Did you eat one before the ganache set?

I kinda hope you did.

Cosmic Brownie Cookies

Rich chocolate cookies topped with smooth ganache and colorful candy pieces, inspired by classic Cosmic Brownies. Soft centers, crisp edges, and a glossy chocolate finish make these cookies irresistible.

Print Pin Rate

Course: Dessert

Cuisine: American

Keyword: Cosmic Brownie Cookies

Prep Time: 30 minutes minutes

Cook Time: 12 minutes minutes

Servings: 12 cookies

Ingredients

For the Cookies

• ½ cup 1 stick unsalted butter softened
• 1 cup packed light brown sugar
• 1 large egg at room temperature
• 2 teaspoons vanilla extract
• 1¼ cups all-purpose flour
• ⅓ cup Dutch-processed cocoa powder
• ½ teaspoon baking soda
• ½ teaspoon salt

For the Ganache

• ⅓ cup heavy cream
• 1 cup semisweet or bittersweet chocolate chips
• Rainbow candy-coated chocolate chips for topping

Instructions

• Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper and set aside.
• In the bowl of a stand mixer fitted with the paddle attachment, cream the softened butter and brown sugar on medium-high speed until light and fluffy, approximately 2 minutes.
• Scrape down the sides and bottom of the bowl. Add the egg and vanilla extract, then beat on medium-high speed until the mixture is pale and well incorporated, about 2 minutes.
• Reduce the mixer speed to low. Add the flour, cocoa powder, baking soda, and salt. Mix just until combined and no dry streaks remain.
• Using a 1½-ounce cookie scoop (approximately 3 tablespoons), portion the dough into evenly sized balls. Roll gently between your hands and place on the prepared baking sheets, spacing cookies about 2 inches apart.
• Bake for 11–12 minutes, or until the cookies are set around the edges but still slightly soft in the center.
• Remove from the oven and allow cookies to rest on the baking sheets for 5 minutes. Transfer to a wire rack and cool completely before adding ganache.
• To prepare the ganache, heat the heavy cream in a microwave-safe bowl until hot but not boiling, about 30–45 seconds. Add the chocolate chips and let stand for 1 minute.
• Stir until the mixture is smooth and glossy.
• Spoon approximately 1 tablespoon of ganache onto each cooled cookie and spread evenly over the top. Sprinkle with rainbow candy-coated chocolate chips.
• Allow the ganache to set at room temperature for approximately 30 minutes before serving.

Notes

To make these cookies gluten-free, substitute the all-purpose flour with a 1:1 gluten-free baking flour that contains xanthan gum. Ensure the cocoa powder, chocolate chips, and candy-coated chocolates are certified gluten-free. Baking time may remain the same, but monitor closely.