Preheat oven to 350°F°F. Spray and line with parchment paper or a silpat mat a 9" x 13" baking dish.
In a medium-sized saucepan over medium heat, add the butter and sugar over low to medium heat. Stir until the sugar has blended into the melted butter.
Once the sugar/butter mixture is melted, remove the pan from the heat and let cool slightly, for about 5 minutes.
To the saucepan, whisk in the eggs, egg yolk, and vanilla extract until well combined.
Whisk the canola oil and the cocoa powder into the saucepan, until well combined.
In a small mixing bowl, whisk together the dry ingredients, the all-purpose flour, baking soda, cornstarch, and salt until well combined.
Gently fold in 1 ½ cups semi-sweet chocolate chips, 1 cup of peanut butter chips, 1 cup roasted peanuts, 1 3⁄4 cups Snickers candy bar pieces, 1 cup of Payday candy pieces, and 1 cup of Twix candy bar pieces into the flour mixture.
Then gently fold the chocolates and candy bar mixture into the butter cocoa until mixed together.
Spread the batter evenly into the prepared baking pan. Sprinkle remaining ingredients on top of the brownie batter.
Bake in the preheated oven for 25-45 minutes or until a toothpick comes out clean.
Remove the brownies from the oven, let cool, about 30-40 minutes. Slice and serve.