Lucky Charms Rice Krispie Treats
Yes, we are making these all in a 9x13 - no pot required! You can customize these Krispies however you wish by changing out the measurements of Rice Krispy cereal to Lucky charm cereal. Up to you! I did mine all with Rice Krispie cereal but have done them both ways.
These Lucky Charms Rice Krispie Treats are the festive St. Patrick's Day twist on the classic treat, made entirely in a 9x13 pan with zero pots to wash. Bright green, studded with rainbow sprinkles and Lucky Charms marshmallows, these are the cutest dessert for any holiday or any time you want to bring something a little extra to a party. They look like they came from a bakery but take 20 minutes start to finish.
The genius of this method is that everything happens in one pan. Butter, marshmallows, vanilla, and cereal all go straight into the buttered 9x13 baking dish, then into the oven for 15 minutes. No melting marshmallows on the stove while stirring constantly. No worrying about scorching. The oven gently melts everything at once, and then you stir in the food coloring and the rest of the cereal in the same pan you bake it in.
What makes this dessert so fun is the customization. The base is just buttered Rice Krispies, but you can make it your own a hundred ways. I went with bright green food coloring and Lucky Charms marshmallows for St. Patty's vibes, but pink for Valentine's, orange for Halloween, red for Christmas, or pastel for Easter all work the same way. Swap out the Lucky Charms marshmallows for chocolate chips, M&Ms, Reese's pieces, or whatever fits your theme.
Cut them into festive shapes with cookie cutters for parties, or just slice into squares for the casual serve. Either way, these are the kind of dessert that makes everyone smile when they walk in the door. Make a batch for the next holiday or 'just because' moment. Let's make them.
📝 Ingredients
- 6 cups Rice Krispy Cereal OR 4 cups Rice Krispy and 2 cups of Lucky Charms Cereal
- 6 TBSP butter + more to butter pan/spatula
- 16 oz bag of marshmallows, divided
- 1 tsp vanilla
- 8 to 10 drops Green food coloring
- Green Festive Sprinkles
- Lucky Charms Marshmallows
👩🍳 Directions
- 1
Preheat oven to 350 and butter (or spray) the bottom and sides of a 9x13 pan
- 2
Add 6 TBSP butter to the bottom of the pan and add in 1 tsp vanilla
- 3
Add in 3/4 of the bag of marshmallows saving some to add in at the end.
- 4
Top with 4 cups of Rice Krispie cereal - do not stir
- 5
Put in 350 degree oven for 15 minutes.
- 6
Remove from oven, add drops of food coloring, then butter a spoon/spatula really well and stir towards the middle of the dish. After a few stirs, add in 2 cups of Rice Krispies (or lucky charms cereal) the rest of the marshmallows and sprinkles. Continue to stir until mixed, but you will need to work quickly here.
- 7
Flatten out in the pan and add extra sprinkles and Lucky charms marshmallow to the top. Let set for at least an hour before cutting. Use a very sharp knife and spatula to remove from pan.
- 8
Store in air tight container or I just store the entire pan in the microwave (don't turn it on!). Best within 2 days.
Ingredient Notes & Substitutions
Rice Krispies cereal: 6 cups total. Or do 4 cups Rice Krispies plus 2 cups Lucky Charms cereal for extra fun. Generic crispy rice cereal works too.
Butter: 6 tablespoons (plus more for greasing the pan and tools). Real butter is essential for flavor.
Marshmallows: One 16-ounce bag of regular marshmallows, divided. 3/4 of the bag goes in first to melt. The remaining 1/4 gets stirred in at the end for marshmallow chunks in the finished treats.
Vanilla extract: 1 teaspoon. Pure vanilla extract for the best flavor. It elevates these from basic to bakery-style.
Green food coloring: 8 to 10 drops liquid, or 1 to 2 drops gel. Adjust based on how vibrant you want the green. Skip if not making them St. Patrick's themed.
Green festive sprinkles: Or any colored sprinkles to match your theme. About 2 tablespoons mixed in plus more for topping.
Lucky Charms marshmallows: Either pulled from a box of Lucky Charms cereal or purchased separately (some grocery stores sell just the marshmallows). Used for topping and folding in for visual pop.
Theme variations: Pink + heart sprinkles for Valentine's. Orange + Halloween sprinkles. Red + green for Christmas. Pastel + jelly beans for Easter. The base recipe works year-round.
How to Store, Reheat & Freeze
Store in an airtight container at room temperature for up to 2 days for the best texture. Holley's tip: storing the whole 9x13 pan covered in the microwave (turned off!) keeps them fresh without taking cabinet space. After 2 days the treats start to harden, so plan to make them within a day of when you want to serve them.
To freeze, wrap individual treats tightly in plastic wrap and store in a freezer bag for up to 2 months. Thaw at room temperature for 30 minutes. The texture stays great after freezing.
What to Serve With Lucky Charms Rice Krispie Treats
These are perfect for St. Patrick's Day parties, school treats, baby showers, kids' birthday parties, or just any festive moment. Pair with a glass of cold milk, hot cocoa, or coffee for a sweet snack. For a St. Patrick's Day spread, serve alongside corned beef and cabbage, Irish soda bread, green sugar cookies, mint chocolate brownies, and green milkshakes. Pack them in a kid's lunchbox for a fun surprise, or wrap individually in cellophane bags for class treats. They are also adorable cut into shamrock shapes with cookie cutters.
💡 Tips for Success
- Butter the bottom and sides of the 9x13 pan really well. Rice Krispie treats are super sticky, and a poorly greased pan means stuck treats. Use real butter or a generous coat of cooking spray.
- Add the butter, vanilla, and 3/4 of the marshmallows to the pan BEFORE preheating the oven. Letting them melt at room temp briefly while the oven heats helps the marshmallows start to soften.
- Save back 1/4 of the marshmallows to stir in at the end. These keep their shape and give you those visible little marshmallow pops in the finished treats. The melted ones make the glue, the un-melted ones make the texture.
- Do NOT stir before baking. Just place everything in the pan and let the oven do the work. Stirring before baking introduces air bubbles and uneven melting.
- Add the food coloring AFTER baking when the marshmallows are fully melted. The food coloring goes in just before you start stirring everything together, so it gets fully incorporated as you mix.
- Use 8 to 10 drops of green food coloring for a vibrant St. Patrick's Day green. Less for pastel green. More for neon green. Gel food coloring works too and gives even more vibrant colors with less liquid.
- Work quickly once you start stirring. The marshmallow mixture cools and firms up fast. You have about 60 to 90 seconds of workable time before things get stiff.
- Butter your spoon, spatula, or hands before pressing the mixture into the pan. Sticky tools mean uneven distribution. A well-buttered spatula gives you that smooth flat top.
❓ Frequently Asked Questions
Can I make these on the stove instead?
Yes. Melt the butter and 3/4 of the marshmallows in a large pot over low heat, stirring constantly. Off heat, stir in vanilla and food coloring, then 6 cups of cereal and the remaining marshmallows. Press into a buttered 9x13 pan.
Can I use all Lucky Charms instead of Rice Krispies?
Yes! Use 6 cups of Lucky Charms cereal. The marshmallow bits in the cereal will partially melt into the treats which is actually delicious. Pull out some of the marshmallows from a separate box to sprinkle on top for visual pop.
What if my treats are too hard?
Too hard usually means too few marshmallows or the mixture cooled too much before pressing into the pan. Use a full 16-oz bag and work quickly. Pressing too firmly into the pan also makes them denser.
What if my treats are too soft?
Soft treats mean too many marshmallows or too much butter. The ratio of 6 cups cereal to 16 oz marshmallows to 6 tablespoons butter is the sweet spot. Stick to it for the perfect texture.
Can I add chocolate?
Yes. Drizzle melted chocolate on top after the treats set. Or fold in mini chocolate chips with the cereal in the last step. Chocolate-dipped corners are also adorable for parties.
How long do they keep?
Best within 2 days. Store in an airtight container at room temperature. Holley's tip of storing the whole pan in the microwave (turned off!) is genius for keeping them covered without taking up cabinet space.
Can I freeze them?
Yes. Wrap individual treats tightly in plastic wrap and freeze in a freezer bag for up to 2 months. Thaw at room temperature for 30 minutes. The texture stays great.
Made this recipe?
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