Opera almond, buttercream and ganache

342kcal / slice

24 slices · 6.6 cm tall · 1.72 kg ?

How is this counted?

A slice is a wedge with about 16 cm² of top — a party slice about 2.5 cm wide at the rim.
Ø 22 cm tin → 380 cm² ÷ 16 = 24 {wslices}.
Height does not add slices, it makes each one heavier: 72 g and 342 kcal a slice here.
Each layer weighs area × thickness × its density; calories are that weight × kcal per 100 g, summed over all layers.

Sponge layers3

TinØ 22 cm

Guests24

moving this resizes the tin

Layers top first

Almond dacquoise: Fold ground almonds into stiff meringue; bake 1 h at 120 °C fan.
Swiss meringue buttercream: Whites and sugar to 71 °C, whip until cool, add butter in cubes.
Dark ganache: Pour hot cream over the chocolate, rest 2 min, stir. Use at 32 °C.