Fun St. Patrick's Day brownies

Celebrate St. Patrick's Day with these whimsical Lucky Charms Marshmallow Brownies that bring together the best of fudgy chocolate and magical marshmallow flavors. These festive treats start with a rich brownie base swirled with marshmallow fluff, then topped with vibrant green marshmallow frosting and a generous sprinkling of Lucky Charms marshmallows. The combination of chewy brownie, gooey marshmallow swirls, fluffy frosting, and crunchy cereal pieces creates an irresistible texture experience that's as fun to make as it is to eat. Perfect for setting beside your leprechaun trap or simply bringing some St. Paddy's Day spirit to your dessert table!

Every year as St. Patrick's Day approaches, I find myself eagerly planning both leprechaun traps and themed treats. These brownies have become a tradition in my home, bringing just the right balance of chocolate indulgence and playful holiday spirit. The first time I served them at a school party, the vibrant green frosting and colorful marshmallows had children and adults alike reaching for seconds before the first batch was gone.

Essential Ingredients and Selection Tips

• Brownie Mix: Choose a fudgy variety rather than cake-like for the best texture. Ghirardelli brownie mix creates particularly rich results, though any high-quality mix works well.
• Marshmallow Fluff: This creates both the gooey swirls in the brownie and the base for the frosting. Look for it in the baking aisle; the consistency is key for proper swirling.
• Lucky Charms Marshmallows: You can either pick these out of the cereal (time-consuming but economical) or purchase them separately in bulk bags, which are often available at Target or online.
• Edible Gold Flakes: These add a magical touch representing the leprechaun's pot of gold. Find them in the baking section of craft stores or specialty food shops.

The quality of your brownie base makes a significant difference in these bars. While any mix will work, choosing one with chocolate chips included (like Ghirardelli Double Chocolate) creates an extra decadent foundation for the other flavors. The first time I upgraded from a basic mix to a premium one, the improvement in flavor and texture was remarkable.

Detailed Cooking Instructions

Step 1: Prepare the Brownie Base

Preheat your oven to 350°F and line a 9-inch square baking dish with parchment paper, leaving overhang on the sides for easy removal. Spray the paper with non-stick cooking spray to ensure nothing sticks. Prepare the brownie batter according to the package instructions, being careful not to overmix, which can create tough brownies. Pour the batter into the prepared pan, spreading it into an even layer with a spatula.

Step 2: Create the Marshmallow Swirl

Drop spoonfuls of marshmallow fluff (about 1/3 cup total) randomly across the surface of the brownie batter. Using a knife or toothpick, gently swirl the marshmallow through the batter, creating a marbled effect. Don't overmix; just a few swirls will create beautiful pockets of gooey marshmallow throughout the baked brownies. The fluff will partially melt into the brownies during baking, creating delicious sweet spots.

Step 3: Bake and Cool the Brownies

Bake the brownies according to the package directions, typically 25-30 minutes or until a toothpick inserted in the center comes out with a few moist crumbs (not wet batter). Allow the brownies to cool completely in the pan on a wire rack. For extra fudgy texture, refrigerate the cooled brownies for 1-2 hours before frosting. This not only intensifies the fudgy quality but also makes them easier to frost cleanly.

Step 4: Prepare the Marshmallow Frosting

In a large mixing bowl, beat two sticks of softened salted butter with an electric mixer on medium speed for about 2 minutes until smooth and fluffy. Add 1½ cups of marshmallow fluff and beat until well incorporated. Gradually add 2 cups of powdered sugar, one cup at a time, mixing on low speed at first to prevent a sugar cloud, then increasing to medium-high. Mix in 1 teaspoon of vanilla extract and add green food coloring gradually until you achieve a vibrant shade. If the frosting is too thick, add 1-2 tablespoons of heavy cream until it reaches a smooth, spreadable consistency.

Step 5: Decorate and Finish

Spread the green frosting evenly over the cooled brownies. While the frosting is still soft, sprinkle generously with Lucky Charms marshmallows, pressing them gently into the frosting so they adhere. Add edible gold flakes for a magical touch reminiscent of leprechaun gold. Refrigerate for about 15 minutes to set the frosting, then use the parchment paper overhang to lift the brownies out of the pan. Cut into squares with a sharp knife, wiping the blade clean between cuts for neat edges.

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My first attempt at these brownies taught me the importance of not overswirling the marshmallow fluff. I initially mixed it too thoroughly into the batter, which caused it to disappear during baking rather than creating distinct pockets of gooey goodness. Now I use a light hand with just a few swirls, which results in those perfect marshmallow surprises throughout the brownies.

Serving Inspiration

These brownies make a festive centerpiece for any St. Patrick's Day celebration. For a themed dessert table, arrange them on a cake stand surrounded by chocolate gold coins and Lucky Charms cereal in small bowls. They're perfect for school parties, office gatherings, or family celebrations. To make them even more interactive, set up a "decorate your own" station with the frosted brownies and various toppings like additional cereal marshmallows, rainbow sprinkles, and edible gold dust, allowing everyone to create their own magical masterpiece.

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Creative Variations

After making these brownies numerous times, I've developed several variations that keep them exciting. For an adult version, add a tablespoon of Irish cream liqueur to the frosting for subtle flavor complexity. During other seasons, adapt the concept by changing the frosting color and toppings - orange with Halloween sprinkles in October, red with crushed candy canes for Christmas, or pink with conversation hearts for Valentine's Day. The basic format of fudgy brownies with marshmallow swirls and creamy frosting works beautifully year-round.

Make-Ahead and Storage Tips

These brownies can be prepared in stages for convenience. The unfrosted brownies can be made up to three days ahead and stored in an airtight container. The frosting can be prepared up to two days in advance and refrigerated - just bring it to room temperature and re-whip before spreading. Once assembled, the brownies will keep well at room temperature for two days or refrigerated for up to a week in an airtight container. For longer storage, freeze unfrosted brownies for up to three months, then thaw, frost, and decorate before serving.

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These Lucky Charms Marshmallow Brownies have become my signature St. Patrick's Day treat, bringing smiles to friends and family each March. There's something undeniably magical about the combination of rich chocolate, fluffy green frosting, and those iconic cereal marshmallows that brings out the kid in everyone. Whether you're actually hoping to catch a leprechaun or simply looking for a festive, delicious way to celebrate the holiday, these whimsical brownies deliver both joy and satisfaction in every colorful, fudgy bite.

Frequently Asked Questions

→ Can I make these brownies from scratch instead of using a box mix?

Absolutely! You can substitute your favorite homemade brownie recipe instead of the box mix. Just make sure it's designed for a 9-inch square pan. The important part is still adding the marshmallow fluff swirl before baking. Once baked and cooled, continue with the frosting and decorations as directed in the recipe.

→ How do I collect just the marshmallows from Lucky Charms cereal?

The easiest way is to pour some cereal into a bowl and pick out the marshmallows by hand. If you need a lot, you can also purchase just the marshmallows online without the cereal pieces. For a fun activity, get kids involved in sorting the marshmallows from the cereal - they can eat the cereal pieces as a snack!

→ Can I make these brownies ahead of time?

Yes! You can make these brownies 1-2 days ahead of time. Store them in an airtight container at room temperature. If your kitchen is warm, you might want to refrigerate them to keep the frosting from getting too soft, but let them come to room temperature before serving for the best texture and flavor.

→ Where can I find edible gold flakes?

Edible gold flakes can be found at specialty baking stores, craft stores with baking sections, or online. If you can't find gold flakes, you can substitute gold sprinkles, gold sanding sugar, or simply omit them. The brownies will still look festive with just the Lucky Charms marshmallows on top.

→ Can I use a different color for the frosting?

Absolutely! While green is traditional for St. Patrick's Day, you can change the food coloring to match any holiday or event - pink for Valentine's Day, orange for Halloween, red and green for Christmas, or rainbow colors for a birthday party. You can even divide the frosting and color portions differently for a multi-colored effect.

→ How should I store leftover brownies?

Store leftover brownies in an airtight container at room temperature for up to 3 days. For longer storage, you can refrigerate them for up to a week - just bring to room temperature before serving. You can also freeze the unfrosted brownies for up to 3 months; thaw completely before adding the frosting and decorations.