Preheat oven to 350 degrees Fahrenheit. Line a cookie sheet with parchment paper and set aside.
In a large mixing bowl or stand mixer, cream the butter, brown sugar, and white sugar together until it is light and fluffy, about 5 minutes. Add the peanut butter and mix well. Then beat the eggs in one at a time and then the vanilla extract until everything is well incorporated.
Now add the flour, baking soda, baking powder, and salt and mix together until just combined. Gently stir in the pretzel pieces, M&M's, and mini chocolate chips until they are evenly dispersed throughout the batter but do not overmix.
Scoop the dough using a cookie scoop or a heaping tablespoon onto the baking sheet. Bake for 8-10 minutes or just until the edges start to brown and the center is baked through. Remove from the oven and place on a cooling rack to finish cooling. Enjoy!