Combine the raspberries with the liqueur and allow to macerate for 1 hour or longer.
Using a 2-in/5-cm cutter, cut 24 rounds from the vanilla sponge.
Using a pastry bag fitted with a #5 plain tip, pipe the lemon mousse into twenty-four 3-in/8 cm hemispherical flexible silicone molds, filling them two-thirds full.