Peanut Butter Bars

This recipe is a minor adaptation of the recipe I make for the Bountiful LDS temple.  It is divine.  There is nothing low fat about it and it is so worth it!

Equipment:
1 cookie sheet
stand mixer with paddle and whisk attachments-it really helps to have one for this recipe.  You can use a hand mixer too but it is a little more diffcult.
bowl scraper (spatula)
*if you have it:  difficult measure measuring tubes, here is the link to check them out.  I highly recommend getting one for the more difficult items to measure, i.e. mayo, peanut butter, coconut oil, etc.
Peanut Butter Measuring Cup
1 large mixing bow
dry measuring cups
measuring spoons
liquid measuring cups
frosting spreader

Ingredients:
Cookie
1/2 C butter
1 C white sugar
3/4 C brown sugar
1 egg
1 tsp vanilla
1 C creamy or chunky peanut butter
1 C all-purpose flour
1 C whole oats
1 tsp baking soda
1/2 tsp salt
 Peanut Butter Spread
1 C creamy peanut butter
1/2 C powdered sugar
1/4 C corn starch
Chocolate Buttercream Frosting
1/3 C butter
4 C powdered Sugar
1/3 C cocoa powder
1/3 C milk

Procedure:
Preheat oven to 325 degrees and lightly grease the cookie sheet and set aside.
In the large mixing bowl, combine all the dry ingredients for the cookie and set aside.
In the stand mixer bowl with the paddle attachment, cream together the butter and both sugars.
Add the egg and vanilla and combine.
Add the peanut butter and mix until completely combined.
Add the dry ingredients as quickly as they will combine without exploding out of the mixer. 
Spread the cookie dough onto the cookie sheet filling the entire sheet. 
Bake for 10-15 mins depending on how your oven heats.  The cookie should look lightly browned and it should have risen while baking.  Take care not to over bake the cookie.  You are aiming for a tender, chewy base to your bars. 

While the cookie is baking, measure out your ingredients for the two frostings. 
Clean the mixer bowl and replace the paddle with the whisk attachment. 
For the peanut butter spread, add the peanut butter to the bowl and whip.
Add the powdered sugar and add only enough corn starch to help absorb some of the oil in the peanut butter; whip till combined.  Don't exceed the 1/4 cup. 
Once the cookie has been removed from the oven,  let it cool and when it is still slightly warm, spread the peanut butter mixture over the entire cookie.  It is easier to spread the peanut butter when the cookie is still slightly warm. 
Then, let it cool completely.

For the chocolate frosting, clean the bowl out once more and use the whisk attachment again.
Add the butter to the bowl and whip.
Add the cocoa powder and then a splash of milk to wet.
Add the powdered sugar, one cup at a time and alternate with the milk till the entire amount of both have been added.
If the frosting is too thick, add 1 T more of milk at a time until a fluffy consistency is reached. 
Spread the frosting over the cooled cookie and try not to eat them all right away!