In a food processor, blitz your oreos until they form a fine crumb. Then put to one side.

Peel and chop the bananas, and blitz in a food processor along with the yoghurt (and condensed milk if using).

Add the oreo crumbs to the yoghurt and bananas and mix well.

Line a 21cm (small) loaf tin with baking parchment, and pour half the yoghurt mixture into it.

Place in the freezer for around 2 hours for it to start firming up. If you don't have time to come back after 2 hours you could place in the freezer with a few strawers wrapped in cling film placed down the middle of the tin. This will create a channel for the caramel if you need to leave overnight.

Pour the caramel on top of the yoghurt mix, in a channel down the centre of the loaf tin.

Pour the remainder of the yoghurt mix into the loaf tin and place in the freezer overnight.

When you have the block of frozen yoghurt ready. Remove from the freezer and place on two upturned glasses inside a baking tray (this will allow you to coat it with chocolate, without the mess).

Melt the milk and dark chocolate together and mix well.

Using a spatula and basting brush smooth the chocolate over the whole block so it is covered. You can leave the bottom as it is.

Place back in the freezer for an hour to allow the chocolate to set.