- Rub the chilled butter into the flour with your fingertips until it resembles breadcrumbs.
- Make a well in the centre. Add the Zùsto, a pinch of salt and the cream and mix everything well by hand. Knead to form a soft ball of dough.
- Cover and set aside to rest for 1 hour at room temperature.
- Pre-heat the oven to 180°C and line a baking tin (approx. 18 cm by 28 cm) with baking parchment.
- Dust your worktop with flour and roll out the dough to about 5 mm thickness. Cut into squares of approx. 5 cm × 10 cm.
- Bake for 25-30 minutes until lightly golden brown.
- Crush the baked biscuits until they resemble fine breadcrumbs, using a rolling pin or a food processor.
- Add the melted butter to the crushed biscuits and mix until combined.
- Pour the mixture into the lined baking tin and press down with the back of a spoon.
- Place in the fridge to cool.
Prepare the sweetened condensed milk:
- Pour the whole milk in a saucepan over medium heat. Stir regularly until steam starts to rise from the milk. Then add the Zùsto gradually to prevent lumps, and continue to stir.
- Reduce the heat and wait until the Zùsto has completely dissolved in the milk.
- Reduce the heat again, but make sure that the milk is still simmering.
- Continue to simmer until the milk reaches the desired thickness. Stir regularly!
- Stir the butter and vanilla essence into the mixture and your condensed milk is ready for use.
- Combine the gelatine with boiling water in a cup and stir until completely dissolved. Add the gelatine mixture to the condensed milk along with the lemon juice. Continue to stir until smooth.
- Remove the baking tin containing the base from the fridge and pour the filling over the base. Return to the fridge to set (approx. 1 hour).
- Combine the strawberries and fruit juice in a heavy-bottomed saucepan over a low heat. Do NOT bring to the boil!
- Dissolve the powdered gelatine in boiling water. Make sure that it has completely dissolved.
- Add the gelatine mixture to the fruit mixture and stir vigorously.
- Allow to cool until it has reached room temperature.
- Remove the baking tin from the fridge and carefully pour the jelly over the slice.
- Return to the fridge to set for at least 6 hours.
Remove from the fridge and cut into squares with a hot knife before serving.