This is the cookie version of a childhood favorite—rich, fudgy brownie-like cookies crowned with a glossy chocolate ganache and those irresistible colorful cosmic brownie chips. I first created this combination one rainy afternoon when I wanted a chocolate treat that felt nostalgic but portable: something you can hand to a friend, pack in a lunchbox, or put out on a holiday platter. The dough bakes into a slightly chewy, almost molten center with crisped edges, and the ganache adds a satin finish that makes each bite feel a touch decadent.

I discovered the winning ratio of butter to sugar and just enough cornstarch to create that tender chew after a few trial batches. What makes these especially memorable is the contrast—soft, chocolatey cookie, smooth ganache, and the playful crunch and color of the cosmic chips. They quickly became my go-to for bake sales and last-minute celebrations, and every time someone takes a bite, you can see the same little flash of recognition that says, "Yes—this is the good stuff."

Ingredients

• Salted butter (1 cup, melted): Use good-quality European-style butter if you can for a richer flavor. Melting integrates easily with the sugars and gives a tender crumb. I often use Plugrá or Kerrygold when I want an extra buttery note.
• Granulated sugar (1 1/4 cups) and light brown sugar (3/4 cup): This combo balances sweetness and chew—brown sugar adds moisture and depth from the molasses.
• Vanilla extract (2 teaspoons): Real vanilla brightens the chocolate; use a pure extract for best aroma.
• Eggs (2 large, room temperature): Room-temp eggs emulsify better with melted butter, giving structure while keeping the interior tender.
• All-purpose flour (1 2/3 cups): Provides structure; measure carefully by spooning and leveling for consistent results.
• Cornstarch (2 teaspoons): A small addition helps keep the center soft and slightly cakey—key for a brownie-like bite.
• Cocoa powder (1 cup): I prefer dark chocolate cocoa powder for depth, but regular unsweetened cocoa works fine.
• Baking soda (1 teaspoon) and kosher salt (1/2 teaspoon): Small leavening boost and salt to balance the sweetness and intensify the chocolate.
• For the ganache: 8 oz semi-sweet chocolate, 3/4 cup heavy cream, 1/2 teaspoon vanilla extract: Use good-quality chocolate bars for a silkier ganache; chips are okay in a pinch.
• Topping: 1 cup cosmic brownie sprinkles: The classic pieces bring color and a slight crunch that completes the texture contrast.

Instructions

Prepare the cookie base: In the bowl of a stand mixer or a large mixing bowl, combine the melted butter with granulated and light brown sugar and vanilla extract. Mix on medium for about 1 minute to dissolve the sugars slightly and incorporate air. Add the room-temperature eggs one at a time, mixing on low until fully combined—the mixture should look glossy and cohesive. Combine dry ingredients: Sift or whisk together the all-purpose flour, cornstarch, cocoa powder, baking soda, and kosher salt. Adding the dry ingredients in one addition and mixing on low prevents overworking the dough; mix just until no streaks of flour remain. The dough will be thick and scoopable—similar to a thick brownie batter. Scoop and chill: Line a baking sheet with parchment paper. Using a medium cookie scoop (about 2 to 2.5 tablespoons), portion 20 even balls of dough and place them on the sheet. Refrigerate for 30 minutes to firm up the butter and limit spread—this step concentrates flavor and helps edges develop without flattening the cookies. Bake: Preheat the oven to 350°F (177°C). Space chilled dough balls about 2 inches apart on the baking sheet. Bake for 9–10 minutes until the edges are just set but the centers still look slightly underbaked—this yields the fudgy interior. Cool the cookies on the sheet for 3 minutes, then transfer to a wire rack to cool completely before frosting. Make the ganache: While cookies cool, chop the chocolate finely if using bars and place in a heatproof bowl. Heat the heavy cream in a small saucepan over medium until it just begins to simmer (do not boil). Pour the hot cream over the chocolate and let sit for 5 minutes to soften. Stir gently until smooth, then add vanilla. Cool 15–30 minutes until thick enough to spread—stir occasionally to check consistency. Assemble: When cookies are completely cool, spread 2–3 tablespoons of ganache on each cookie, leaving about 1/4 inch border so the cookie edge shows. Sprinkle the cosmic brownie chips immediately so they adhere to the ganache. Serve at room temperature or refrigerate briefly to set the topping.

Storage Tips

Store finished cookies in an airtight container at room temperature for up to 3 days; if your kitchen is warm, refrigerate to prevent the ganache from softening too much. For longer storage, freeze assembled cookies on a tray until solid, then transfer to a freezer bag for up to 2 months. To thaw, move to the refrigerator overnight or let them sit at room temperature for 30–60 minutes. When reheating a refrigerated cookie for a softer ganache, let it sit at room temperature for 20 minutes or warm gently in a 200°F oven for 3–4 minutes.

Ingredient Substitutions

If you prefer a dairy-free version, substitute vegan butter and full-fat coconut cream for the ganache—note the flavor will shift to coconut. For a darker chocolate profile use Dutch-process cocoa and increase sugar by 2–3 tablespoons if you want less intensity. Swap semi-sweet chocolate for bittersweet in the ganache for a more adult finish. To make them gluten-free, use a 1:1 gluten-free flour blend designed for baking; add a tablespoon of xanthan gum if the blend lacks it to maintain structure.

Serving Suggestions

Present these on a simple white platter so the ganache and cosmic chips pop visually. Pair with a tall glass of cold milk, espresso, or a scoop of vanilla ice cream for a contrast in temperature and texture. For parties, stack on a tiered tray and garnish with extra chips or a dusting of cocoa powder. They work beautifully with berry compotes for a balance of acidity against the deep chocolate.

Cultural Background

The cosmic brownie chip originates from a nostalgic boxed brownie product popular in American childhood lunches. This version translates that iconic flavor and look into a hand-held cookie. While brownies and cookies have long intersected in American baking, this hybrid celebrates that crossover: the fudgy center of a brownie merged with the convenience and shareability of a cookie—perfect for modern gatherings where portability matters.

Seasonal Adaptations

In winter, add a pinch of cinnamon or orange zest to the dough for seasonal warmth. For the holidays, swap the cosmic chips for red and green sprinkles or chopped peppermint candy for a festive crunch. During summer, keep the ganache slightly looser and serve chilled with fresh berries to lighten the experience. For a fall twist, stir in a tablespoon of espresso powder to the dry ingredients to deepen the chocolate flavor.

Meal Prep Tips

Make a double batch of dough and freeze half as pre-scooped balls on a tray; transfer to a freezer bag and bake directly from frozen, adding 1–2 minutes to the bake time. Prepare ganache up to 48 hours ahead and keep refrigerated; bring to room temperature and whisk briefly before spreading. Pack finished cookies in single layers with parchment between if transporting, and aim to frost close to serving time to keep the chips vibrant.

These cosmic brownie cookies are one of those recipes that bridge generations—familiar yet upgraded. Whether you bake them for a crowd or for a quiet afternoon treat, I hope they bring the same warm smiles to your kitchen as they do to mine.