Pre-heat oven to 350 F. Butter a square baking dish.
Heat oil in a non-stick frying pan. Fry bread in batches, about 2 ½ minutes each side, till golden brown. Set aside.
Bring milk to boil and lower heat. Add ground saffron and cardamom, and let it simmer for 10 minutes. Remove from heat.
In the meantime, beat eggs and sugar in a large bowl till well-mixed.
Pour milk into the egg and sugar mixture, and beat again.
Pour custard over bread, and bake uncovered for 25 minutes.
Top with crushed pistachios.