Store it in a cake box in the fridge for up to 4 days.
Freeze baked and cooled down sponge cake wrapped in plastic wrap and then in a piece of foil for up to 2 months. Thaw in the fridge overnight before assembling the cake.
Store cooled down lemon curd in an air-tight container in the fridge for up to 2 weeks. You can also freeze it for up to 2 months and thaw it in the fridge overnight before using it.