Heat the grill to high. Place the halved tomatoes on a tray and cook under the grill for 10-15 mins until golden and starting to wrinkle.
In a small bowl, mix together the beaten egg, milk, caster sugar and chives until combined. Dip the bread triangles into the mixture until fully absorbed.
Heat a pan to high and add the oil. Fry the eggy bread for 2 mins each side, until golden. Serve with the grilled tomato halves.