180°C, 350°F, Gas Mark 4
Serves 16

Ingredients

Invert two (or more if you have them) 9-inch round cake tins; grease and flour the bottom of the tins. Beat butter in mixer bown ultil smooth. Beat in sugar until light and fluffy. Add eggs one at a time, beating well after each addition. Beat in vanilla. Beat in flour and salt until just combined. Spread 1/3 cup batter evenly on each inverted cake tin to within ¼ inch of the edge. Bake 10 to 12 minutes, until lightly browned around edges. With long, thin metal spatula, loosen each wafer and transfer to wire racks to cool completely.

Repeat on buttered, floured pans with remaining batter to make a total of 12 wafers. (Can be made ahead. Stack between sheets of wax paper and cover tightly, up to 2 days).

Coffee buttercream: Heat milk in medium saucepan over medium heat to just boiling. Meanwhile, whisk egg yolks and sugar together in a medium bowl. Gradually whisk in hot milk. Return mixture to saucepan; cook, stirring constantly, over medium-low heat until mixture thickens and coats back of spoon, about six minutes (Do not boil). Strain through sieve into mixing bowl. Stir in coffee powder and vanilla. Cool to room temperature. Beat in 2 cups of butter, 1 tablespoon at a time, beating well after each addition.

To assemble, place 1 cake wafer on serving platter. Spread evenly with 1/3 cup buttercream. Add second wafer and 1/3 cup more buttercream; repeat with remaining wafers and buttercream, ending with a wafer. Pipe remaining buttercream decoratively on top. (Can be made ahead. Cover and refridgerate up to 24 hours). Remove from refridgerator 30 minutes before serving.