Kill the cookies in portions with a blender into small crumbs.
Place the cookie crumbs in a bowl and add the melted butter. Mix well.
Cover a mold 24-26 cm in size with parchment and tamp a mass of cookies and butter along the bottom of the mold. Put the mold in the refrigerator for a while while the berry layer is preparing.
Transfer black currants to a saucepan, cover with sugar.
Beat with a hand blender.
Put the stewpan on the fire. Bring the mixture to a boil and immediately remove from heat. Cool to room temperature.
Add sour cream to the berry mass, mix.
Pour over instant gelatin with water, leave for 5 minutes to swell, then heat until completely dissolved. Pour gelatin into the sour cream and berry mixture, mix.
Take the mold out of the refrigerator. Pour the berry mass onto a layer of cookies and refrigerate for 4-6 hours, until completely solidified.
Separate the finished mousse cake from the mold and transfer to a beautiful plate, decorate as you wish, for example, with current berries and mint leaves.