Preheat your oven to 350°F (175°C) and prepare three 8-inch round cake pans by greasing and lining with parchment paper.

In a large mixing bowl, combine all-purpose flour, unsweetened cocoa powder, granulated sugar, baking powder, baking soda, and salt. Whisk until well blended.

Add large eggs, whole milk, vegetable oil, and vanilla extract to the dry ingredients. Mix until smooth.

Gently stir in hot coffee until just mixed.

Divide the batter among the prepared pans and bake for 25-30 minutes. Cool in pans for 10 minutes, then transfer to wire racks.

In a medium saucepan, whisk together granulated sugar, cornstarch, and egg yolks. Gradually add the orange juice, stirring constantly.

Cook over medium heat until thickened, about 5-7 minutes. Remove from heat and stir in orange zest and butter.

Heat heavy cream in a saucepan until steaming. Pour over chopped dark chocolate and let sit for 5 minutes before stirring until smooth.

Place the first cake layer on a plate and spread cooled orange filling on top. Add the second layer and repeat.

Top with the final cake layer. Pour ganache over the cake, letting it cascade down the sides.

Garnish with fresh orange slices or candied peel.