Separate eggs, place egg whites on a bowl with cream of tartar.

In a bowl, place egg yolks, melted butter, yogurt, coffee powder, milk, milk powder, salt, whole eggs and plain flour. Mix well.

Make meringue – whisk egg whites with cream of tartar until frothy, gradually add in granulated sugar and continue to whisk until medium peak.

Using a spatula, slowly mix the two mixtures together until combined.

Divide batter to 3 portions of equal weight, preheat oven to 180ºC. Pour the batter on a 14 x 14 inch tray lined with parchment paper. Bake in oven for 20 minutes until cooked. Once cooked, divide the sponge to two equal size portions.

Place sugar on a saucepan and cook until caramelized, add in butter and cream, turn off heat and stir to combine. Combine the caramelized sauce, salt, banana and spread evenly on a baking pan, bake in preheated oven for 10 minutes, keep aside.