Cookies are the same No Fail Sugar Cookies with Royal Icing tinted Halloween purple that I used for making the Fall Cookies.
The topper is made of molded chocolate. I got the mold recently at Candyland Crafts in Somerville and the Slime Green candy melts I used are from Michaels. These toppers are super easy to make. Just melt candy melts in a microwave, spoon into the mold cavities. Tap on the counter top to release bubbles, and place in the fridge for about 10-15 minutes. They pop out easily once chilled.
The Hershey's Perfectly Chocolate chocolate cake is my go to chocolate cake recipe now. I have used it before to make the Ganache cake. So far it has not failed me.
The buttercream is a new recipe that I was a bit skeptical about because it uses flour, and is cooked like a pudding, but it turned out very well in the end. The texture was a bit too soft for piping rosettes but I think it was coz' the kitchen was very warm with all the baking. I think about 5 to 10 mins in the fridge should have firmed it up nicely. It was a bit too salty for my taste so next time I plan to sub with unsalted butter and some salt to taste.
Here's the recipe and tutorial from another blog Our Best Bites: