Preheat oven to 350 degrees. Grease and flour a 13x9 inch baking dish.
Prepare cake per the package instructions. Pour into prepared dish and bake for 20-25 minutes, until a tester comes out clean.
Remove from the oven and poke holes all over the top of the cake.
Heat the hot fudge for 30 seconds, until relative smooth. Pour over the cake while hot. Sprinkle mint baking chips over the top. Let cool completely.
In a bowl mix together pudding mix and 2 cups of milk for 2 minutes. Pour over cooled cake. Place in fridge and let stand for about an hour.
Whip heavy cream to soft peaks. Slowly add sugar and mint extract. Beat until stiff peaks. Add food coloring, if using, and stir until combined.
Spread whipped topping over the top of the cake. Sprinkle with Chopped candies.
Store in the fridge.