Giant Peanut Butter Oatmeal Cookies – Peanut Butter Cookies with Oats and Reese’s Pieces

Giant Peanut Butter Oatmeal Cookies aren’t just giant, they are monstrous. Made with rolled oats and Reese’s Pieces, these peanut butter cookies are a real treat.

I’m in love with anything peanut butter, and in my book, the bigger the better. That’s why I love these giant peanut butter cookies. Giant cookies always remind me of going to the mall when I was younger. It was always a treat to stop at the food court cookie shop for a giant chocolate chip cookie!

Ingredient List for Peanut Butter Cookies with Oats Instead of Flour

The crazy thing about these cookies is there’s no all purpose flour in the recipe. Instead of flour, regular rolled oats (not instant oats) are used. The recipe calls for 4 1/2 cups of rolled oats which is a lot, but there’s no flour whatsoever in the recipe. This helps give a chewy texture.

• Butter, softened
• Granulated Sugar
• Brown Sugar
• Large Eggs
• Creamy Peanut Butter
• Vanilla Extract
• Light Corn Syrup
• Rolled Oats (not quick oats)
• Baking Soda
• Reese’s Pieces
• Walnuts, chopped

They are similar to a monster cookie, like this recipe using leftover candy, that doesn’t have flour in it either.

Peanut Butter Cookies with Oats and Reese’s Pieces

My dear friend Katy inherited a collection of old cookbooks when she recently purchased a new house. The previous owner passed away, and most of her possessions came with the house. Katy is a dear, and knows that I am a vintage cookbook addict, so she passed them on to me.

In the collection was a darling 1986 Christmas Cookie Cook Book. It’s a treasure trove of cookie recipes, perfect for Christmas baking, or baking any of the year for that matter. That’s where I found the recipe for Peanut Butter Cookies with Rolled Oats.

How to Make Chewy Peanut Butter Oatmeal Cookies

Step by Step Instructions

1. Preheat oven to 350 degrees F.
2. Cream softened butter; add both sugars and beat well in a large mixing bowl.
3. To the creamed mixture, add peanut butter, eggs, vanilla extract and light corn syrup; beat well.
4. Stir in old fashioned oats, baking soda and salt.  Then, stir in Reese’s Pieces and chopped walnuts.
5. Spoon dough in 1/4 cup measurements about 4 inches apart on the cookie sheet.  Press the cookie dough into a 3 inch circle.
6. Bake 12 to 15 minutes. The center of the cookie should be slightly soft.
7. Cool slightly on the baking sheet; then remove to a wire rack.

Storage Instructions

Let cookies cool to room temperature. Store in an airtight container on the counter.

For the full ingredient amounts and recipe steps for how to make chewy peanut butter oatmeal cookies, scroll to the recipe card at the bottom of this post. 

Giant Peanut Butter Oatmeal Cookies Recipe FAQs

• If needed, use margarine instead of butter.  Just be sure to start with it softened to room temperature.
• Candy such as M&Ms would be a great substitute for Reese’s Pieces, if desired.
• Omit chopped walnuts, if desired, or try swapping in chopped pecans instead.
• The cookie batter will be stiff.
• Use approximately 1/4 cup batter, or the amount that fits in a large cookie scoop or ice cream scoop.
• Press the cookie batter into a 3-inch circle.
• Leave plenty of room between the cookies on the cookie sheet; they will spread when baking.
• Check out our Amazon Store for our favorite kitchen and pantry items.

How to make chewy vs crunchy cookies?

To achieve a chewy cookie, try using butter as your fat in the recipe. Also, try brown sugar instead of white sugar. Brown sugar has more moisture which will give you a more moist dough. Lastly, do not overbake your cookies.

Peanut Butter Dessert Recipes

Old Fashioned Peanut Butter Balls 

Rice Krispies Scotcheroos 

Homemade Peanut Butter Pie from Scratch

Peanut Butter Trifle 

Peanut Butter Cornflake Drop Cookies