Oversized Oatmeal Cream Pie/Sandwich

For my hubby's birthday, since he's not much of a cake person, I wanted to make him a big cookie instead.  As I was searching for a recipe, I came across this and knew it was perfect.  If you've ever had (and enjoyed) a Little Debbie Oatmeal Creme Pie, this treat is for you.  The one I made came out bigger than the original blogger's version; I think it spread a bit more than hers did, which may be the fault of the egg I used or it may have needed slightly more flour (I believe the latter, as the dough seemed on the 'wet' side).  It was still amazingly delicious and made for the perfect little birthday cookie pie :)  P.S. the cookie piece tore off this way, I hadn't eaten any yet!

Original recipe:
http://sallysbakingaddiction.com/2014/02/03/1-giant-oatmeal-creme-pie/

Ingredients:

--cookie dough--

1/2 c. + 1 T. all-purpose flour (possibly more)
1/2 c. quick oats
3/8 tsp. baking soda
1/4 tsp. ground cinnamon
1/4 c. unsalted butter, softened
1/2 c. light or dark brown sugar, packed
1 large egg
1/2 tsp. vanilla extract

--cream filling--

3 T. unsalted butter, softened
2/3 c. powdered sugar
1 T. heavy cream (or half & half, and may need slightly more)
1/4 tsp. vanilla extract (clear, if you have)
pinch salt


Instructions:

1. Heat oven to 350°F.  Line a large baking sheet with parchment paper and set aside.

2. For the cookie dough: in a medium bowl, combine flour, oats, baking soda, and cinnamon.  Set aside.

3. In mixing bowl of stand mixer, beat butter on high speed until creamy, about 1 minute.

4. Add brown sugar and beat until combined.

5. Add the egg and vanilla extract, beat until combined.

6. Add the dry ingredients mixture.  Mix on low until just combined; the dough will be sticky, but should hold shape (if not, add a little more flour).

7. Scoop half of dough onto one corner area of parchment and other half onto opposite corner area.  Form each into ball/round shape.

8. Bake for 20-22 minutes or until lightly browned at edges.  (I went for 22 and forgot to check towards the end, thus mine got a bit darker than intended.)

9. Remove from oven and cool for 15 minutes on baking sheet before transferring to rack.  (Since mine was a little past the golden point, I only left it on for a couple of minutes before transferring parchment to cooling racks.  I removed from the parchment after it had cooled the rest of the way.)

10. For the filling:  in stand mixer bowl (or bowl for handheld mixer, like I used), add butter and beat for 1 minute.

11. Add remaining ingredients and beat together until combined.  If mixture is too thick, add very small amounts of cream until it is just thick enough to be a creamy spread.  (I did not have to add any.)

12. Spread filling on one layer of cookie and top with other to make sandwich.  Tear off a piece and enjoy!