Mix the bananas together with the honey and the pecan nuts. Divide the mixture equally between 2 slices of the bread, leaving a slight space along the edges of the bread. Top with the other 2 slices to make 2 sandwiches.
Heat a frying pan over a moderate heat. Crack the eggs into a bowl and beat in the milk. Dip both sides of the banana sandwiches in the egg mixture. Melt the butter in the frying pan. Fry each sandwich gently for 3 to 4 minutes, turning halfway through cooking, until nicely coloured and warmed through.
Dust with the icing sugar, cut in half and serve with the Greek-style natural yoghurt.