Preheat oven to 200°C and line three 23cm springform tins with paper, grease with butter, and dust with flour.
Whisk eggs and sugar over simmering water until thick, then remove from heat and whisk for three minutes.
Stir in melted butter and fold in sifted flour before baking in two tins for 25 minutes.
Cool sponges for five minutes, remove from tins, and sprinkle with raspberry liqueur.
Mix one and a half punnets of raspberries with liqueur and icing sugar until dissolved.
Pulse remaining raspberries and heat in a pan with caster sugar until dissolved.
Stir squeezed gelatine into the warm raspberry mixture until dissolved, then add whole raspberries.
Whisk cream to soft peaks and fold into the cooled raspberry mixture.
Assemble by layering sponge, three-quarters of the mousse, the second sponge, and remaining mousse.
Decorate with strawberries and mint, then chill in the fridge until set.