Blend the biscuits in a blender or crush them with a rolling pin in an oven bag. Add the softened butter.
Mix well with the fork, to get buttery crumbs. Distribute into 4 dessert cups and smooth them out, to make a biscuit layer. It needs to take up 1/3 of the cup's volume. Put in the fridge to harden.
Put 1 tsp (5 g) of the gelatin in a small bowl and pour 2 tbsp of cold water over it. Leave it to swell, heat it until it melts and then leave to cool. Add it to the cheesecake and stir again until fully absorbed.
Distribute into the cups, while you try to make it the same height as the biscuit layer. Return to the fridge, in order for the cream to harden.
Prepare the orange gelatin as follows: strain the orange juice at least 3 times through a fine sieve.
If the oranges are really sweet, there's no need of adding extra sugar, but you can sweeten with it if you like, by stirring until fully dissolved. Dissolve the remaining gelatin in 2 tbsp cold water, leave it to swell, heat and cool.
Add it to the juice and stir well. Distribute among the cups, pouring the orange juice mixture up to the very rim of the cups. It's best to pour it into the cups after you've already placed them in the fridge, in order not to move them again before they harden.