Preheat your oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Stir in the rolled oats and peanut butter until evenly distributed.
Fold in the chopped Halloween candy.
Drop rounded tablespoons of dough onto the prepared baking sheets, about 2 inches apart. For a softer center, slightly flatten the tops of the cookies.
Bake for 9-12 minutes, or until the edges are lightly golden brown and the centers are still soft.
Let the cookies cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.
Notes
For extra soft cookies, slightly underbake them.
You can use any leftover Halloween candy you have on hand.
To achieve a festive look, use candy eyeballs and brightly colored M&M’s.
These cookies can be stored in an airtight container at room temperature for up to 3 days.
For a gluten-free option, use a gluten-free all-purpose flour blend and ensure your oats are certified gluten-free.