Pre-heat the oven to 200°C/400°F/Gas Mark 6.
Cut the plums into quarters, remove the stones and place them in a baking dish.
Scatter over the soft brown sugar and dot with 15g of the butter.
Bake uncovered in the oven for 15 minutes.
Meanwhile, beat the eggs in a bowl, add the cinnamon, orange rind, milk and caster sugar and whisk until combined.
Slice the hot cross buns in half.
Soak them in the egg wash for a couple of minutes.
Fry them in the remaining butter in batches until golden on both sides.
Keep them warm in the oven while you cook the rest.
Serve topped with the baked plums and drizzled with maple syrup.