Frankenstein Halloween Rice Krispie Treats

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These Halloween Rice Krispie treats are the perfect last-minute addition to your dessert line-up – Fast, easy and made from just a few store bought ingredients.

halloween rice krispie treat decorated with candy melts/sprinkles to look like frankenstein leaning against a glass of milk with a light green pumpkin, green candles and more rice krispie treats in the background.

Halloween may be my favorite time of year, but it also always ends up being one of the busiest – and it just seems to slide right into the chaos that is Thanksgiving and Christmas.

So if the thought of decorating the house, planning and/or making the kids’ costumes, organizing the trick-or-treat group or Halloween party on top of everything else going on in your life has you thinking “Arggggh everything is happening all at once plz make it staaaaap”, this post is for you.

These Halloween Rice Krispie treats are not only delicious (uuuummm, marshmallows anyone?), easy and made from just a few store bought ingredients, but perfect for enlisting your kids’ help to make.

Baking Halloween memories? These are the best kind.

Prefer to watch the process?

Here’s how to make these rice krispie treats

First, make the rice krispie bars.

Grease a 9″ x 13″ casserole dish with cooking spray.

In a large pot over low-medium heat, melt the butter. Add the marshmallows and stir until smooth.

A note about heat: While it may be tempting to turn that heat up to get the marshmallows and butter to melt faster, this can lead to overcooking, which can ultimately make the bars hard.

Once the marshmallows are melted, remove the pot from the heat and stir in the rice krispie cereal and until its evenly coated. I like to use a spatula for this step.

Spoon the rice krispies into the prepared casserole dish and press into place. A large measuring cup works well for this.

Allow to set for 30 minutes.

rice krispie treats in a glass casserole dish with blue silicone webbing around the outside.

Second, prepare the bars and the candy melts.

Once the bars have set, remove them from the dish and cut them into rectangles of various sizes.

Pour the green candy melts into a bowl. Place over a pot of boiling water (double boiler) and cook, stirring occasionally, until the candy melts are completely melted.

A note about double boilers: The advantage to using a double boiler instead of microwaving the chocolate is that it’s harder (although not impossible) to over-cook it and it’s great for keeping the chocolate warm while you work. If you don’t have a double boiler or don’t want to use one, you can melt your chocolate in the microwave using 10 second increments.

If the candy melts are overly thick, you can thin them out by adding a teaspoon of vegetable shortening. Don’t worry, this won’t affect the flavor.

rectangularly sliced rice krispie treats of various sizes on a gray backdrop.

Finally, decorate your bars.

Dip the top of each rice krispie treat into the green candy melts and then into the black jimmies sprinkles.

Add two royal icing eyes and place on a cooling rack to set.

rice krispie treat on a gray background dipped in green candy melts and black sprinkles with bowls of candy melts, royal icing eyes and sprinkles around it.

In a small bowl, melt the black candy melts in the microwave using 10 – 15 second increments, heating just until they can be stirred smooth.

Pour the candy melts into a piping bag and pipe stitches onto your treats.

Allow to set completely before packaging.

frankenstein decorated rice krispie treat next to a bag of black candy melts and royal icing eyes.

Expert tips

Cooking rice krispie treats: Make sure to cook your butter/marshmallows over medium heat and to remove them from the heat immediately once melted to avoid overcooked, hard bars.
Keep your kitchen equipment/utensils free of water when melting the chocolate. Getting water in the melting/melted chocolate will cause it to seize.
Using chocolate in place of candy melts: If you’d prefer to use chocolate in place of the candy melts, you can use white chocolate with green gel food coloring and dark chocolate with black gel food coloring to replace the green and black candy melts.
Don’t have a double boiler? You can melt your chocolate in the microwave using 10 second increments. Just be careful, it’s very easy to over-cook chocolate this way.
If the chocolate is too thick: You can thin it by adding a little bit of vegetable shortening. Stir a little bit in, stirring until it’s completely melted and test to see if it’s the consistency you want. A little bit goes a long way.
Storage: Rice krispie treats can be stored in an air tight container at room temperature and are best when eaten within three days.

partially eaten rice krispie treat next to a glass of milk, a bowl of royal icing eyes and whole rice krispie bars.

Frequently asked questions

What can I use instead of marshmallows in Rice Krispies?

If you don’t have marshmallows on hand or would prefer not to use marshmallows, peanut butter and honey (or maple syrup) make an excellent substitute. For a recipe of this size you’d need 3/4 cup peanut butter and 3/4 cup honey (or maple syrup).

Why do my Rice Krispie treats get hard?

Rice Krispie treats can harden as they go stale, but if they’re fresh, overcooked marshmallows is the most likely culprit. Be sure to cook your marshmallows over medium (or even low) heat and immediately remove them from your stovetop once they’ve melted.

Why are my Rice Krispie treats not sticking together?

Did you know that the best Rice Krispie treats require a fresh bag of marshmallows? If you used an old bag, the stale marshmallows may have dried out just enough to keep your treats from sticking together.

Do Rice Krispie treats need to be refrigerated?

No, Rice Krispie treats can be stored at room temperature, but if you need them to last more than a few days, you can freeze them. Wrap each square and freeze them for up to three months.