Lightly brush the mould with oil. Mix 1 tbsp. icing sugar and cornstarch and generously dust the oiled mould with it. Pass 250 g icing sugar through a fine sieve into a mixing bowl. Mix gelatine with 150 ml cold water in a saucepan, allow to swell for about 2 minutes.
Then heat up while stirring, dissolve and boil up briefly.
Immediately add the hot gelatine mix to the icing sugar and beat with the whisk of the mixer for approx. 4 minutes until a foamy mass is formed, until a thick, creamy tip is formed. Immediately pour the marshmallow mixture into the mould and smooth it down with an oiled dough scraper.
Place in the refrigerator for at least 1 hour.
Break the chocolate into pieces, place in a bowl and melt over a warm water bath while stirring. Remove the marshmallow mixture from the mould and cut approx. 25 squares (each approx. 3 x 3 cm) with a lightly oiled knife.
Spread a teaspoon of caramel spread onto each square 1⁄2-1. Cover generously with chocolate, refrigerate for another 30 minutes.