One-Bowl, Big-Batch Monster Cookie Bars

I found this recipe on the blog fivehearthome.com to make for the annual Chili Cook Off Bake Off.  No flour!  

4 eggs
1 1/2 cups sugar
1 cup light brown sugar
3/4 teaspoon salt
1 tablespoon pure vanilla extract (I always use double vanilla)
16 ounce jar (2 cups) peanut butter (I used Skippy Natural)
5 tablespoons unsalted butter, at room temperature
2 1/2 teaspoons baking soda
5 cups old fashioned oats (Not Quick Oats)
1 cup M&M's (Mini M&M's would be best but I couldn't find them)
1/2 cup semisweet chocolate chips (I used mini's here)
1/2 cup peanut butter chips (I used Reese's chips and mini cups)

Position rack in center of oven and preheat oven to 350 degrees.  Generously butter (yes butter not PAM) in an 18 x 13 x 1 rimmed sheet pan.  Set aside.

In a very large bowl using electric mixer,  mix together the eggs and sugars until well-combined.  Beat in the salt, vanilla, peanut butter, and butter until smooth. Stir in the baking soda and the oats, then add the M&M's, chocolate chips and peanut butter chips and mix until just combined.

Spread the batter into the prepared baking pan, pressing down and smoothing the top into an even layer.  Bake for 18 - 22 minutes.  (I baked for 20 minutes) or until edges are very light golden brown and center is set.  

Allow to cool in the baking pan before slicing and serving.