Banana Frozen Yogurt

Whizz the bananas in a food processor until smooth, then add the yogurt, sugar and lemon juice and whizz to combine then put in an ice-cream machine (it takes about 30 mins in mine). It may be still quite soft, so scoop it out in individual portions and put in the freezer to harden up a little more for about another 30 mins (if it's in the freezer for longer than this, take it out 10 mins before you're ready to serve it).

You can make it without an ice-cream machine too - put the mixture in the freezer for an hour, take it out and whisk with electric beaters to get rid of ice crystals, then refreeze for about 4 hours.