Toast the oats (I usually do this the night before): melt the butter in a frying pan, add the oats and toast them, stirring constantly and sprinkling in sugar little by little.

Mix the sour cream with the sugar. In a separate bowl, pour the boiling water over the gelatin and stir quickly until fully dissolved. Let it cool slightly, pour into the sour cream mixture and stir.

Slice the bananas into rounds.

Assemble the dessert in jars in layers: sour cream, banana, oats - then sour cream, banana, oats again. Alternate however you like. Enjoy!