Grandma Shirlie’s Monster Cookies

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With Halloween upon us, it is time to make one of my favorite treats from Grandma Shirlie…Monster Cookies.  Not only does the name scream Halloween, it is also delicious.  How could you not like a cookie that has peanut butter, chocolate chips, oatmeal, and M&M’s?

Ingredients for monster cookies: butter, vanilla extract, peanut butter, oats, sugar, eggs, chocolate chips and M&M's

First step is to mix the sugar and butter together…

Pouring sugar for monster cookies

Mixing softened butter and sugar for monster cookies

Then you add an egg and mix this in…

Adding egg into sugar and butter mixture for monster cookies

Next comes the fun part of adding the oats, peanut butter, chocolate chips and M&M’s!

Add oats for monster cookies

Creamy peanut butter into mixture of oats, sugar, and butter for monster cookies

Fall colored M&M's and chocolate chips for monster cookies

I like to then use a tablespoon to place the dough on the cookie sheet…

Tablespoon to place dough on cookie sheet for monster cookies

Grandma Shirlie's Monster Cookies


  • 1 cup sugar
  • 1 cup light brown sugar
  • 1 stick of butter, softened
  • 3 eggs
  • 1 1/2 cups of peanut butter
  • 4 1/2 cups quick cooking Quaker Oats
  • 1 tsp. vanilla (I like to use a little extra)
  • 1/2 lb. M&M's (I just use what I think is right)
  • 12 oz. package of semi-sweet chocolate chips


Pre-heat oven to 350 degrees.

Mix sugar and butter together, then add eggs and beat.

Then add the remaining ingredients. I find that it's good to add the oats first and mix that well.

I then add the peanut butter and mix, followed by the chocolate chips and M&M's.

Line cookie sheet with parchment paper (since this makes several batches parchment paper makes it easier.)

Drop by spoonful on cookie sheet.

Bake for 12 minutes. They may not look quite done, but they are.

Here they are before they go in the oven…

Monster cookies before placing them in the oven

Don’t they look so good?!  And trust me, you have to eat them with milk and you certainly can’t have just one 🙂

Monster Cookies with milk (contains sugar, oats, peanut butter, chocolate chips, and M&M's) Perfect for Halloween!



Visit I Heart Nap Time where we have linked this recipe as well!

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