Preheat the oven to 350°F. Line 2 baking sheets with parchment paper.
Sift together the all-purpose flour, baking powder, baking soda and salt. Set aside.
Using an electric stand mixer, cream together the softened butter, light brown sugar, granulated sugar, peanut butter and vanilla. Beat for 3 minutes until smooth, fluffy and light beige in color.
Add the eggs one at a time beating well after each addition. Stop to scrape the bowl periodically so all of the ingredients fully combine.
Add the dry ingredients gradually while beating on low speed continue until all of the dry ingredients have been added, stopping to scrape the sides of the bowl as needed.
After all of the dry ingredients have been added, increase the speed of the mixer and beat for 1 minute.
Use a large non-stick spatula or spoon to mix the cubed Snickers bars, pretzels, peanuts, and chocolate chips into the batter by hand. The batter will be stiff. Mix until the ingredients are evenly distributed.
Use a 2 oz ice cream scoop to separate the dough. Place the dough rounds at least 3-inches apart on the baking sheet to allow room to spread. Press the centers to flatten slightly for even baking. (A 4 oz ice cream scoop will make jumbo cookies so, adjust baking time accordingly)
Bake for 18 minutes rotating the pans if needed, until golden.
Cool on the cookie sheet for 5 minutes, then remove to a cooling rack to cool completely.
Depending on the size you choose to make these cookies, the baking time may need to be adjusted slightly. Large cookies will take longer to bake, likewise smaller cookies, less time.