Preheat oven to 350°F (177°C). Grease two 8×2 inch cake pans. (Make sure they’re at least 2 inches high, deep dish style.) Set aside
Make the cake: Whisk the flour, cocoa powder, baking soda, baking powder, and cinnamon together in a large bowl. In another large bowl using a handheld or stand mixer fitted with a paddle or whisk attachment, beat the butter, granulated sugar, eggs, and vanilla, and zucchini together until combined. pour the dries in and alternate with adding the buttermilk
Pour batter evenly into cake pans. Bake for around 25-32 minutes or until the cakes are baked through. To test for doneness, insert a toothpick into the center of the cake. If it comes out clean, it is done. Allow cakes to cool completely in the pans set on a wire rack. The cakes must be completely cool before frosting and assembling.
For the Frosting: melt chocolate chunks/ chips is 30 second intervals (I do this about 3 times, do not overmelt) the chocolate should NOT be runny but rather thick
add the heavy cream
then add the sugar and cocoa and sour cream and mix
let the mixture come to room temp. do not worry, it will not harden if you used chocolate chips :)
Assemble and frost: First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand or serving plate. Evenly cover the top with frosting. Top with 2nd layer and spread the remaining frosting all over the top and sides. Pipe any leftover frosting on top. (I used Ateco #30 tip.) Decorate with chocolate sprinkles or mini chocolate chips if desired. Slice and serve. Cover any leftover cake and store at room temperature for 2-3 days or in the refrigerator for up to 5 days.