01 -
Preheat the oven to 350 degrees Fahrenheit and spray a 9x13 pan with non-stick baking spray.
02 -
Melt the butter in a microwave-safe bowl for 30 seconds.
03 -
In a large bowl, mix together the melted butter, brown sugar, and granulated sugar. Allow the mixture to cool for 2-3 minutes. Then add eggs, egg yolk, and vanilla extract, stirring to combine.
04 -
In a separate medium-sized bowl, whisk together the flour, cornstarch, baking powder, and salt.
05 -
Add the dry ingredients to the butter mixture and stir until combined. Mix in the chocolate chips and Easter M&Ms.
06 -
Pour the mixture into the prepared pan and spread it out evenly.
07 -
Bake in the preheated oven for 20-25 minutes.
08 -
Remove the pan from the oven and carefully place the Peeps on top of the cookie bars. Place back into the oven for an additional 5-10 minutes.
09 -
Remove the pan from the oven, let it cool for 5-10 minutes, and then serve.