Peel and slice the kiwi fruit. Peel the mango and cut into small pieces. Peel and slice the bananas. Mix the fruits with lemon juice and 1 tablespoon sugar, cover and cool.
Roast the oat flakes in a pan without fat until golden brown, turn and set aside.
Melt 1 tablespoon sugar in a pan. Add the butter and oatmeal, mix well with the sugar and allow to cool.
Mix the yogurt with lemon zest and 1 tablespoon sugar.
Arrange the salad in a bowl. Scatter the toasted oatmeal on top.