Preheat your oven to 350°F (175°C). Butter and line the bottom of cake pans with parchment paper. Sift together flour, cocoa powder, baking powder, baking soda, and salt.

In a separate bowl, cream the unsalted butter and sugar until light and fluffy, about 3-5 minutes. Add in the eggs, vanilla extract, milk, and hot brewed coffee, mixing until just combined.

Pour the batter into prepared pans and bake for 15-20 minutes, checking for doneness with a toothpick.

Place sealed cans of condensed milk in a pressure cooker, ensuring they are submerged in water. Cook on high for about 35 minutes.

Carefully release the pressure and allow the cans to cool completely before opening. Store-bought dulce de leche can also be used.

In a heatproof bowl, combine egg whites and sugar, whisking over simmering water until the mixture reaches 140°F (60°C).

Remove from heat, and whip the mixture on high speed until stiff peaks form. Gradually incorporate softened butter, mixing well before adding melted chocolate, dulce de leche, and espresso powder.

Remove the cooled chocolate cake layers from their pans. Place one layer on a serving plate and pipe a ring of buttercream around the perimeter.

Fill the center with a generous dollop of dulce de leche before topping with the second layer. Repeat until all layers are stacked. Apply a crumb coat of buttercream around the entire cake and chill for about 30 minutes.

Heat heavy cream to near boiling, then pour it over finely chopped chocolate. Stir until smooth and glossy. Allow it to cool slightly to thicken.

Using a piping bag, drip the ganache around the edges of the cake, letting it cascade down. Spread remaining ganache on top. Optionally, drizzle additional dulce de leche over the top.

Refrigerate your cake for a few hours or overnight before serving. This allows all the layers to meld beautifully.

When ready to serve, slice into the cake and enjoy it with a scoop of vanilla ice cream or a dollop of whipped cream.