Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the softened butter and creamy peanut butter. Cream them together until smooth and fluffy. Gradually add in both the brown sugar and granulated sugar, beating until well combined.
Add the eggs, one at a time, mixing well after each addition. Then, pour in the vanilla extract, mixing until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, baking soda, baking powder, kosher salt, and rolled oats until evenly mixed.
Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Be careful not to overmix.
Gently fold in the chocolate chips and candy-coated chocolate pieces until evenly distributed throughout the dough.
Using a cookie scoop, drop portions of dough onto a lined baking sheet, spacing them about 2 inches apart. Bake for 10 to 12 minutes.
Remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a wire rack.
