Classic Monster Cookies
If you’re on the hunt for a cookie that combines the best of all worlds—sweetness, crunch, and a hint of nostalgia—look no further than Classic Monster Cookies! These delightful treats are packed with peanut butter, oats, chocolate chips, M&Ms, and walnuts, making them a crowd-pleaser at any gathering. Whether you’re baking for a special occasion, a school event, or just to satisfy a sweet tooth, these cookies are an absolute must-try. Get ready to whip up a batch that will have everyone clamoring for more!
Reasons to Love Classic Monster Cookies

Classic Monster Cookies are not just any ordinary cookies; they are a celebration of flavors and textures. Here are a few reasons why you’ll adore them:
- Versatile Ingredients: With a blend of oats, peanut butter, and chocolate, they provide a satisfying and hearty bite.
- Customizable: You can easily modify the recipe by adding your favorite mix-ins like dried fruits or different types of nuts.
- Easy to Make: The steps are simple and straightforward, perfect for bakers of all levels.
- Great for Sharing: These cookies are perfect for parties, potlucks, and bake sales, making them ideal for sharing with friends and family.
What You’ll Need
To create these delicious Classic Monster Cookies, gather the following ingredients:
- 1 cup of salted butter, at room temperature
- 2 ½ cups brown sugar
- 2 cups sugar
- 6 eggs
- 2 tablespoons vanilla extract
- 2 ½ cups peanut butter
- 4 teaspoons baking soda
- 9 cups quick oats
- 1 ½ cups chocolate chips
- 1 cup chopped walnuts
- 1 pound M&Ms, plus more to garnish
Before You Start: Equipment
Before diving into the recipe, make sure you have the following equipment ready:
- Mixing Bowls: A large bowl for mixing wet ingredients and another for dry ingredients.
- Electric Mixer: An electric mixer will make creaming the butter and sugars effortless.
- Measuring Cups and Spoons: Accurate measurements are key to perfect cookies.
- Baking Sheets: Line them with parchment paper for easy cleanup.
- Spatula: A sturdy spatula will help mix in the oats and other ingredients.
Classic Monster Cookies: From Prep to Plate

Ready to bake? Follow these step-by-step instructions for Classic Monster Cookies that will have everyone coming back for seconds!
Step 1: Preheat the Oven
Preheat your oven to 350°F (175°C). This ensures that your cookies bake evenly and turn golden brown.
Step 2: Cream the Butter and Sugars
In a large mixing bowl, combine 1 cup of salted butter, 2 ½ cups of brown sugar, and 2 cups of sugar. Using your electric mixer, cream these ingredients together on medium speed until the mixture is light and fluffy, about 3-5 minutes.
Step 3: Add the Eggs and Vanilla
Next, add in the 6 eggs, one at a time, mixing well after each addition. Then, pour in the 2 tablespoons of vanilla extract and continue to mix until everything is well combined.
Step 4: Mix in the Peanut Butter
Now it’s time for the star ingredient! Add the 2 ½ cups of peanut butter to the mixture. Beat until fully incorporated and smooth.
Step 5: Combine Dry Ingredients
In a separate bowl, whisk together 4 teaspoons of baking soda and 9 cups of quick oats. Gradually add this dry mixture to the wet ingredients, mixing until just combined.
Step 6: Fold in the Goodies
Using a spatula, gently fold in 1 ½ cups of chocolate chips, 1 cup of chopped walnuts, and 1 pound of M&Ms. Be careful not to overmix; you want to keep those delicious chunks intact!
Step 7: Scoop the Dough
Using a cookie scoop or a tablespoon, drop heaping amounts of dough onto prepared baking sheets, leaving space between each cookie to allow for spreading.
Step 8: Bake
Place the baking sheets in the preheated oven and bake for 10-12 minutes, or until the edges are lightly golden. The centers may look slightly underbaked—that’s perfect!
Step 9: Cool and Garnish
Once baked, remove the cookies from the oven and let them cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely. If desired, top with a few extra M&Ms for that finishing touch.
International Equivalents

If you’re following this recipe from outside the United States, you might find these equivalents helpful:
- 1 cup of butter = 227 grams
- 1 cup of brown sugar = 220 grams
- 1 cup of sugar = 200 grams
- 1 tablespoon = 15 milliliters
- 1 pound of M&Ms = 450 grams
Author’s Commentary
As a baking enthusiast, Classic Monster Cookies hold a special place in my heart. They remind me of childhood baking sessions with my mom, where we would mix everything in a giant bowl and sneak spoonfuls of dough when no one was looking. The combination of peanut butter, oats, and candies makes each bite a delightful surprise. Whether you’re enjoying them fresh out of the oven or a few days later, these cookies never disappoint!
Leftovers & Meal Prep
Classic Monster Cookies can be stored in an airtight container at room temperature for up to a week. For longer storage, consider freezing them. Place the cookies in a single layer on a baking sheet, freeze until solid, then transfer to a freezer-safe bag. They can be enjoyed straight from the freezer or thawed at room temperature. Perfect for meal prep or when you have unexpected guests!
Your Questions, Answered
Can I use creamy or crunchy peanut butter?
Absolutely! You can use either creamy or crunchy peanut butter depending on your texture preference. Both will give you delicious cookies.
Can I substitute the oats with flour?
For this recipe, quick oats provide a unique texture and flavor. If you prefer to use flour, consider using a blend of half flour and half oats for a similar result.
How do I store leftover cookies?
Store leftover Classic Monster Cookies in an airtight container at room temperature. They will stay fresh for about a week. For longer storage, freeze them as mentioned above.
Can I add other mix-ins?
Yes! Feel free to customize your Classic Monster Cookies with other mix-ins such as dried fruit, different types of chocolate, or even coconut for a tropical twist!
Time to Try It
Now that you have the recipe and all the tips, it’s time to gather your ingredients and start baking! Classic Monster Cookies are sure to become a favorite in your household. Happy baking!

Classic Monster Cookies
Ingredients
Equipment
Method
- Preheat your oven to 350°F (175°C).
- In a large mixing bowl, combine the butter, brown sugar, and sugar. Cream together until light and fluffy, about 3-5 minutes.
- Add the eggs one at a time, mixing well after each addition. Then, add the vanilla extract and mix until combined.
- Add the peanut butter and beat until fully incorporated and smooth.
- In a separate bowl, whisk together the baking soda and oats. Gradually add to the wet ingredients, mixing until just combined.
- Fold in the chocolate chips, chopped walnuts, and M&Ms gently.
- Scoop heaping amounts of dough onto prepared baking sheets, leaving space for spreading.
- Bake for 10-12 minutes, or until edges are lightly golden.
- Cool on the baking sheet for 5 minutes, then transfer to a wire rack. Garnish with extra M&Ms if desired.
Notes
- Store cookies in an airtight container at room temperature for up to a week.
- Freeze cookies for longer storage; they can be enjoyed straight from the freezer.
- Feel free to customize with mix-ins like dried fruits or different chocolates.
