Professional reference formula

Yield: one 20 × 20 cm / 8 × 8 inch cake.

All quantities and process choices on this page are external professional evidence.

  • Three thin 20 cm joconde sheets
  • 200 g strong coffee and 100 g sugar for syrup
  • 300 g coffee buttercream
  • 250 g dark chocolate ganache
  • 200 g dark chocolate glaze
  • Tempered chocolate for the base, optional

Method

  • Bake thin, even joconde sheets and cool flat.
  • Boil the coffee syrup and cool.
  • Brush the first sheet with a thin chocolate barrier if used, invert, then soak evenly.
  • Build thin, level layers of coffee buttercream, joconde, ganache, joconde and remaining buttercream, soaking each sponge consistently.
  • Chill until firm, glaze at a temperature that flows without melting the buttercream, then trim and portion with a warm dry knife.

Professional identity

Opéra is a low rectangular French layer cake of thin almond joconde soaked with coffee syrup, coffee buttercream and chocolate ganache, finished with a smooth chocolate glaze. Thick sponge or tall modern entremet formats materially change the classical structure.

Critical controls

  • Keep every layer deliberately thin and level.
  • Measure syrup distribution; patchy soaking is visible in the cut.
  • Allow ganache to crystallise to spreadable consistency.
  • Glaze only a thoroughly chilled, flat surface.

Evidence status

external_evidence; no Tanya-specific formula, ingredient choice or production practice is implied.