These rich, fudgy brownies are perfectly moist and dense, with a deep chocolate flavor that melts in your mouth. Topped with a silky ganache and a sprinkle of sea salt… because balance is everything!

Prep Time: 25 minutes
Cook Time: 25 minutes
Total Time: 1 hour, 30 minutes
Yield: 16 bars

Ingredients

• 1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
• 3/4 cup (150g) granulated sugar
• 1 large egg + 1 egg yolk
• 2 teaspoons pure vanilla extract
• 1 and 1/2 cups (188g) all-purpose flour (spooned & leveled)
• 1/4 teaspoon salt
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1 and 1/2 teaspoons cornstarch
• 1/2 cup (80g) rainbow sprinkles (not nonpareils)

Vanilla Frosting

• 3/4 cup (12 Tbsp; 170g) unsalted butter, softened to room temperature
• 2 and 1/4 cups (270g) confectioners’ sugar
• 3 Tablespoons (45ml) heavy cream or half-and-half
• 1 teaspoon pure vanilla extract
• salt, to taste
• optional: food coloring (I used 1 drop red for this pink frosting) and extra sprinkles for decorating on top

Instructions

1. Make the bars: Preheat oven to 350°F (177°C). Line an 8-inch square pan or 9-inch square pan with aluminum foil, making sure to leave enough overhang on the sides. Set aside.
2. In a large bowl using a handheld mixer or stand mixer fitted with a paddle attachment, cream the softened butter for about 1 minute on medium speed. Get it nice and smooth, then add the sugar on medium speed until fluffy and light in color. Beat in egg, egg yolk, and vanilla. Scrape down the sides as needed.
3. In a medium bowl, whisk together the flour, salt, baking powder, baking soda, and cornstarch. With the mixer running on low speed, slowly add the dry ingredients to the wet ingredients in 3 different parts. The dough is quite thick. Once combined, gently fold in 1/2 cup sprinkles using a silicone spatula (or by mixing on low speed).
4. Press the cookie dough evenly into the prepared baking pan. Bake for 25-26 minutes or until very lightly browned on top. You want the cookie bars to be extra soft, so careful not to overbake. Allow the bars to cool completely on a wire rack at room temperature before frosting. The center will slightly sink that’s normal.
5. Make the frosting: If you don’t want a super thick layer of frosting as pictured, halve the frosting recipe. With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cream, and vanilla extract with the mixer running on low. Increase to high speed and beat for 3 full minutes. Add more confectioners’ sugar if frosting is too thin or more cream if frosting is too thick. Add a pinch of salt if frosting is too sweet. I usually add anywhere between 1/8 – 1/4 teaspoon of salt. Beat in food coloring, if using.
6. Remove cooled bars from the baking pan using the aluminum foil overhang on the sides. Frost the bars with a thick layer of frosting and decorate with extra sprinkles if desired. Cut into squares. Use a very sharp knife and wipe off with a paper towel between each cut to make neat, even cuts. Store bars in an airtight container at room temperature for up to 2 days and in the refrigerator up to 5.

Notes

1. Make Ahead & Freezing Instructions: You can make these bars and the frosting 1 day in advance– store the bars, covered, at room temperature overnight and store the frosting, covered, in the refrigerator. Frost before cutting and serving. You can also freeze the unfrosted bars for up to 3 months. Thaw overnight in the refrigerator, frost, cut, and serve.
2. Special Tools (affiliate links): 8-inch Square Pan or 9-inch Square Pan | Electric Mixer (Handheld or Stand) | Glass Mixing Bowl | Whisk | Silicone Spatula | Cooling Rack
3. Eggs: Room temperature egg and egg yolk preferred. To bring the egg to room temperature quickly, place in a warm glass of water for about 10 minutes as you get the other ingredients ready. Or just set out when you set out the butter to soften 1 hour ahead of time.
4. Sprinkles: Use regular sprinkles (aka “jimmies”) in the cookie bar base. Nonpareils (the little balls) will bleed their color and turn the sugar cookie dough green/purple/brown. I order my sprinkles in bulk here.
5. Cream: Cream or half-and-half is preferred for creamiest, fluffiest frosting. Keeping that in mind, milk would be an OK substitute if you do not have either on hand.
6. Larger Batch: You can double this recipe and bake in a 9×13-inch pan; the bake time is about 35 minutes.