Pour some boiling water over abura-age to remove any excess oil. Set aside.
Pour 250ml tsuyu into a saucepan with 500ml water. Heat up over a medium heat.
Remove soup from heat just before it boils and add abura-age. Return to heat and allow to simmer for approximately 10 minutes before adding udon.
Once noodles have simmered for a further 10 minutes, pour some into a bowl with a little of the soup and a piece of the abura-age. Garnish with shichimi chilli powder and sliced spring onions.