Preheat oven to 350°F and glaze three (7-inch, 2-inch-deep) round cake pans with butter, before lining their bottoms with parchment paper.
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Take a bowl and put water, cocoa, and espresso powder inside for heavy mixing. After a smooth texture is attained milk and vanilla are added and whisked thoroughly. Sift flour, baking soda, and salt in another bowl and set aside.
Take a large bowl and use an electric beater to mix butter and brown sugar till the solution becomes fluffy. The eggs are added next, one at a time, and are beaten thoroughly. Let this be mixture A. Now add the flour and the cocoa mixtures to the mixture A, and mix at low speed. Continue to do so until there is no discontinuity in the mixture.
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Divide the batter in the pan and bake for about 30 to 35 minutes. Cool them on the rack for about 30 minutes, before removing the paper and allowing them to cool down completely.
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Next is the preparation of Ganache. Simmer the cream in a pan and gradually mix the chocolate, mix it until the solution is smooth. Put the solution in a bowl and let it refrigerate for about 4 hours, stirring intermittently so that it thickens, not too much though.
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The last part is to assemble the cake. Spread one layer of cake and pout around 2/3rd cup of Ganache on it. Repeat the steps. Chill the cake for about one hour so that Ganache get firm.
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