First, prepare the chocolate cake. Preheat the oven to 350°F.
Melt the chocolate, butter, and sugar in a double boiler until the chocolate and sugar have dissolved.
Let the mixture cool slightly, then stir in the eggs.
In a bowl, combine the flour, cocoa powder, baking soda, and salt. Add the wet ingredients and knead everything into a smooth dough.
Divide the dough into 6 equal portions. Roll out each portion on parchment paper to the size of the springform pan.
Bake the layers one after another for 6–8 minutes each, until firm but still soft.
Let the layers cool completely.
Now, for the buttercream, beat the softened butter with the powdered sugar until fluffy. Stir in the honey and sour cream until smooth.
Spread the buttercream on each layer and stack the layers in the springform pan. Refrigerate the cake for at least 4 hours, or preferably overnight, to allow it to set.
Make the glaze by melting the chocolate and butter into the heavy cream using a double boiler.
Stir the mixture until smooth and pour it over the chilled cake. Spread the glaze evenly and let it set before serving.
