Grease & Flour 2 8-inch round cake pans, Preheat oven to 350 degrees F.
Mix all cake ingredients together on medium until smooth. Cake mixture should be quite thick.
Separate the batter evenly between the two cake pans, using a spatula to spread the mixture to the edges.
Bake for 30-35 minutes, or until a toothpick can be inserted and come out clean. Cool cake completely.
Using a food processor or coffee grinder, grind the pistachios. If you don't have these, using the flat end of a knife, crush the pistachios. Your filling will be chunkier, but still delicious.
In a stand mixer, whip goat cheese, honey, vanilla, and pistachios on high, until well combined.
Add heavy whipping cream, and continue to whip on medium-high until the whipped cream stiffens up (about 1-2 minutes). VERY IMPORTANT: There are a lot of "wet," high-fat ingredients in this mixture. If you over beat, it will break down and become a goopy mess.
When finished, set filling aside.
Whip butter for 2 minutes until very fluffy.
Add cocoa powder 1/4 C at a time until smooth.
Alternate adding powdered sugar and heavy whipping cream (or milk) until smooth.
Mix in vanilla at the very end.
Putting Together the Cake
After cake has cooled completely, cut each round in half. In between layers carefully spread the pistachio filling.
Frost the outside with chocolate frosting, and garnish with pistachios.
Helpful Tip: I like to prepare my cakes a day or two in advance. When they've cooled, I wrap them in Saran Wrap and freeze overnight (or for up to a month). This allows the cake to be easier to cut and frost, and holds moisture in.