Preheat your oven to 325°F (160°C) and prepare a ¼ sheet pan by lining it with parchment paper and spraying lightly with cooking spray.

In a large mixing bowl, sift together the all-purpose flour, baking powder, baking soda, salt, chocolate pudding mix, cocoa powder, sugar, and brown sugar. Mix well until evenly combined.

In another bowl, whisk together the eggs, buttermilk, brewed coffee, vegetable oil, and vanilla extract until fully combined.

In a microwave-safe bowl, melt the salted butter and semi-sweet chocolate chips together in the microwave in 30-second intervals.

Pour the wet ingredients into the dry mixture gradually and stir gently until just combined, then add the warm chocolate mixture and whisk until smooth.

Pour the batter into the prepared pan and let it sit for 5-10 minutes to settle, then bake for 22-26 minutes, or until a toothpick comes out clean.

Allow the cake to cool in the pan for about 10-15 minutes. Wrap in plastic wrap and place in the freezer.

In a small saucepan, heat the heavy cream until just simmering, then remove from heat and stir in the chocolate chips until smooth.

In a mixing bowl, whip together the softened butter, cream cheese, and shortening until smooth. Gradually add powdered sugar.

Slice the chilled cake into layers, spread peppermint ganache between each layer, apply a crumb coat of buttercream, and frost the exterior.