Frankenstein Cookies

Half chocolate, half vanilla – but with a hidden peanut butter cup stuffed inside. This partly black, partly electric green cookie gives off serious Frankenstein vibes.

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This cookie was made purely for fun. I wanted to create a Halloween cookie that had the aesthetic to it, but also with a hidden surprise. I wanted to try and make a cookie that was inspired by Frankenstein with the black and the green, but not necessarily a cookie that was using royal icing, or buttercream to create the effect. I opted for this much easier and simpler version of cookie that can be made by anyone in their home.

The recipe isn’t anything over the top, and there are no ‘special’ ingredients involved. This recipe is simple and straightforward. It does require food coloring to achieve the electric green (obviously), but other than that this recipe is easy!

These cookies are also so fun to make with kids! My almost 4 year old son helped me with these cookies (and almost all cookies for the last few weeks), and he thoroughly enjoyed himself. We opted to stuff these cookies with a miniature Reese’s peanut butter cup because I hadn’t incorporated any actual peanut butter into any of the cookies I’ve been developing. And truth to be told – I am not a big peanut butter cookie fan. But I figured a cookie stuffed with a PB cup wouldn’t be so bad…and I was right! 🙂

Notes Prior To Baking

Cocoa Powders: as with most Halloween cookies, I try to use black cocoa powder wherever I can do I can avoid the black gel food coloring. This recipe uses black cocoa powder and dutch cocoa powder. Only a small amount is needed of each. Also, make sure you are sifting your cocoa!! Cocoa will tend to clump, and if not sifted into the dough then you’ll find some parts of the dough with clumps of cocoa powder that can be difficult to break down after added.

Green Food Coloring: I used Neon Bright Green food gel from Chef Master to achieve this vibrant green in the cookie. After separating the dough ? and ?, I colored the ? dough with the green food gels. Use food safe gloves if you can or else you risk getting green food coloring all over your hands or clothes.

Miniature Reese’s PB cups: I used the miniature Reese’s PB cups to stuff these cookies vs. the regular sized PB cups. The miniatures are much easier to handle and fit perfectly in the middle of this cookie when using the 2 tbsp cookie scoop.

Butter & eggs: I allow my unsalted butter to reach room temperature before I microwave. It allows me to only microwave the butter for 25 seconds or less to achieve the melted butter without making it too hot (and then having to wait to allow to cool before adding eggs). If you don’t have time to allow the butter to come to room temperature than you will need to microwave longer than the 25 seconds and then allow butter to cool a few minutes before proceeding with adding the eggs.

Refrigeration & storage: I refrigerate the cookies after prep for a minimum of 12 hours, or up to 24 hours. If you’ve made some of my other recipes before then you know this is a common theme for me. I like to allow my ingredients to set within one another to allow all those flavors to mesh together so once they are baked you have yourself a very flavorful cookie. These cookies freeze extremely well too! Just make sure you are freezing in freezer safe ziplock bags. They keep frozen for about 3 months. To defrost you simply need to remove the entire bag from the freezer and place on kitchen counter. Allow to come to room temperature for a few hours, and then enjoy.

Tools For The Job

kitchen scale

2 tbsp ice cream scoop


mesh strainer/sifter

parchment paper or silicone baking mat

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Frankenstein Cookies

Sharon Alvarenga
Half chocolate, half vanilla – but with a hidden peanut butter cup stuffed inside. This partly black, partly electric green cookie gives off serious Frankenstein vibes.
5 from 1 vote
Prep Time 30 minutes
Cook Time 12 minutes
Chill Time 12 hours
Course Dessert, Snack
Cuisine American
Servings 12 cookies


  • 260 g all purpose flour 2 c
  • 165 g unsalted butter, room temperature ¾ c
  • 150 g sugar ¾ c
  • 1 large egg room temperature
  • 1 large egg yolk room temperature
  • 2 tsp vanilla extract
  • 2 tbsp black cocoa powder
  • 1 tbsp dutch cocoa powder
  • ¼ tsp baking soda
  • ½ tsp salt
  • neon green food gel
  • 12 mini Reese's peanut butter cups


  • Place butter in a large bowl and microwave for 25 to 30 seconds until almost completely melted. Remove from microwave and whisk until butter has evenly melted. Add sugar and vanilla and whisk until well combined. Add eggs and whisk until fully combined. Add flour, baking soda and salt to wet ingredients and whisk until all the flour has been incorporated. You will then divide the dough as ? and ?. The ? dough will be the dough that has the cocoa powders. Once divided, sift in both cocoa powders into the ? dough, and then use a rubber spatula to evenly fold in. This may take a few minutes, but make sure you fold the cocoa powders in evenly. Once done, move to the ? dough. Place 3 to 4 drops of the neon bright green food gel coloring into the dough, and then mix in until evenly combined. You can use your hands to mix (I recommend using food safe gloves), or just use a spatula to mix.
  • You will then divide the ? black dough in half, and place on opposite sides of the bowl. Then take the green colored dough and place between those two black parts of dough. Then using the 2 tbsp ice cream scoop, scoop from one end to the other making sure you come out with the cookie scoop full of dough. Then take one of the mini Reese peanut butter cups and stuff into the scoop full of dough. The dough will escape on parts of the side and that’s ok! Push into the dough until its almost flush with the bottom edge of the scoop. Then fold over the dough has been pushed out over the PB cup. Place cookie dough on baking sheet, and then repeat until all the dough has been used. Place cookies into refrigerator for a minimum of 12 hours, or up to 24 hours.
  • Preheat oven to 350 F. Remove cookies from refrigerator and bake for approximately 13 – 14 minutes. Remove from oven and place on wire rack to cool. Allow to cool completely before enjoying.
Keyword chocolate cookie, halloween cookies, peanut butter cup
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  1. 5 stars
    These are great! So easy and so fun! I went with orange for the vanilla cookie dough and used frozen teaspoons of Nutella for the centers. Thanks for sharing the recipe!

    1. Thank you so much Ana for trying the recipe and giving us all the idea to add Nutella!

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