First set out butter, milk, and one large egg. We want the butter to soften and the cold ingredients to reach room temp. before baking. Measure out all ingredients in advance for fuss-free baking.
Pre-heat oven to 350°F.
First make the cookie cake. In a large bowl, cream together softened butter, brown sugar, and granulated sugar with an electric hand mixer until well-mixed and creamy in consistency.
Add in the egg and vanilla and continue to beat with the mixer to incorporate.
In a separate bowl, mix together flour, cornstarch, baking soda, and salt.
Add flour mixture to the larger bowl slowly while you continue to beat on low.
Once your dough is mixed, fold in chocolate and peanut butter chips.
Place a sheet of parchment paper on the bottom portion of an un-greased springform pan (to prevent sticking) and lock in the sides.
Press in your dough and bake on the center rack for 18-22 minutes. Mine is usually done in 20 since I like a softer center. Once your cookie cake has finished baking, flip your oven to broil on HIGH and watch it like a hawk. After about a minute the top will brown to golden perfection, still leaving that soft slightly cookie dough-esque center intact. Turn off broiler and remove from oven with mitts.
Allow cookie cake to completley cool before icing and/or slicing. Cake will be very soft in the center and set while it cools.
TO MAKE THE FROSTING
To make the buttercreamfrosting, use an electric hand mixer to whip softened butter until creamy.
Sprinkle in powdered sugar in three batches, while mixing until fluffy and fully incorporated.
Beat in vanilla, then add milk to thin the frosting as needed to reach desired consistency. I added 3 TBSP. Beat in milk for an additional 3-4 minutes.
TO MAKE THE WREATH
Portion 1/4 cup frostign for the berries, half the remaining batter for the light green swirls, and the other half for the darker green parts of the wreath.
Use gel food coloring to dye the frosting. Red for the berries, light green for half the wreath, darker green for the remaining wreath frosting.
Portion both green frostings into the same piping bag (fitted with a large star or french star tip) by simply spreading it into rows with a small silicone spreader/spatula. Pipe green frosting around the edges of the cookie cake, twisting and turning as needed to make a wreath design. For the berries use a small ziploc bag or piing bag and fill with red frosting. Simply cut the tip and pipe it directly onto the wreath. Top with optional sprinkles.
A large star piping tip and piping bags come in handy for the frosting. Have fun with it and don't forget to tag me in a photo if you take one - I can't wait to see your cookie cake decor!Serves 10 or more depending on slice size.Nutrition Facts below are estimated using an online recipe nutrition calculator. Adjust as needed and enjoy!