Preheat the oven to 350° F (180° C).

Using a stand mixer or an electric hand mixer, cream together the butter and sugars until light in color and fluffy in texture.

Scrape down the sides and add in the eggs, corn syrup, vanilla and milk. Mix until thoroughly combined.

Next, add the flour, cocoa, corn starch, baking soda, and salt. Mix until your chocolate cookie dough forms. The dough will be soft.

Add in the m&m candies and peanut butter chips and mix gently just until distributed throughout the dough.

Portion out the dough using a # 24 scoop (roughly 2 1/2 Tbsp), roll and press powdered sugar onto each ball of dough. Lightly press down on the dough ball before baking.

Bake at 350°F (180° C) for 8-10 minutes until the cookies have flattened, spread and have started to crackle.

Allow the cookies to cool on the pan for 10 minutes prior to transferring to a wire rack.

While the cookies are cooling, make the ganache. Measure out the heavy cream into a microwave-safe bowl.

Microwave the cream for 1 1/2 minutes or until it is boiling.

Remove the bowl from the microwave and add in the chocolate and peanut butter chips. Use a spoon and push the chips around so they are all covered by the heavy cream.

Allow the chocolate and peanut butter chips to sit in the hot cream for 3-5 minutes.

After the time is up, use a whisk and stir the chips into the heavy cream until smooth. If some of the chips have not melted, feel free to pop into the microwave for 15 seconds.

Spread ganache onto each cookie and quickly top with a few whole pieces of puppy chow, some mini m&ms, and some festive sprinkles.

Store in an airtight container at room temperature for 3-5 days.