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

In a large mixing bowl, sift together the all-purpose flour, unsweetened cocoa powder, granulated sugar, baking powder, baking soda, and salt.

Add the large eggs, whole milk, vegetable oil, and vanilla extract. Blend on medium speed until smooth and well combined.

Stir in the hot coffee to deepen the chocolate flavor and achieve a thinner batter consistency.

Divide the batter among the prepared pans and bake for 25-30 minutes, or until a toothpick comes out clean.

Allow the cakes to cool in pans for 10 minutes, then invert onto a wire rack to cool completely.

In a medium saucepan, whisk together granulated sugar, cornstarch, and egg yolks. Gradually add fresh orange juice while stirring and cook over medium heat until thickened.

Remove from heat, stir in the orange zest and butter, and let cool to room temperature.

Heat heavy cream in a saucepan until steaming, pour over chopped dark chocolate, and stir until smooth to make ganache.

Assemble the cake by layering the cake layers, spreading orange cream filling in between, and pouring ganache on top.

Garnish with fresh orange slices or candied orange peel before serving.