Monster Peanut Butter Cookies

  • Author: Loody's Kitchen
  • Prep Time: 10 minutes
  • Cook Time: 10 minutes
  • Total Time: 20 minutes
  • Yield: 16 large cookies 1x


Giant Monster Peanut Butter Cookies, loaded with oats and m&m candies. Since there’s no chill time required, these are perfect last minute cookie craving!



  • 1/2 cup butter, room temperature
  • 3/4 cup brown sugar
  • 1/2 cup creamy peanut butter
  • 1 teaspoon vanilla extract
  • 1 egg
  • 1 cup flour
  • 2 cups old fashion oats
  • 1/2 teaspoon baking soda
  • 3/4 cup m&m candies


Preheat oven to 350°

In the bowl of a stand mixer fitted with the paddle attachment, cream together butter and brown sugar until fluffy (3-4 minutes). With mixer still running, add in peanut butter, vanilla and egg. Cream for another 2 minutes until combined.

With mixer running on low, add dry ingredients (flour, oats, baking soda) until just combined then use a spatular to fold in m&m candies gently. If you’re adding extra add-ins, stir them in here as well.

Scoop using a 3 or 4 tablespoon cookie scoop (big monster cookies are the way to go) and place on a parchment or silicone baking mat lined cookie sheet. Flatten dough slightly, as this dough won’t spread significantly.

Bake for 8-10 minutes, cookies should be soft in the middle and just golden on the edges. Do not over bake these or they will dry out – better to air on the less done side! Let cool slightly, then devour…cookie monster style.

Yields 16 very large cookies. Keeps at room temperate 3-4 days, in the fridge for a week or in the freezer up to 2 months.


I use salted butter in pretty much all my recipes, so I often don’t add more salt to my baked goods. If you don’t have salted butter, add 1/4 teaspoon salt to this recipe. You can add up to 1/2 cup more mix-ins such as coconut shreds, chocolate chunks, nuts with the recipe as is. Or decrease the amount of m&ms to 1/2 cup and add up to 3/4 cups of other mix-ins.

Keywords: monster cookies, peanut butter monster cookies, oatmeal peanut butter cookies