Celery and Potato Soup for 4

Scaled to serve 8

100.0 g of margarineheattosssimmer 30minblend
900.0 g of celerycut into 1.5cm pieces
550.0 g of potatoespeeled, cut into 2.5cm cubes
1800.0 ml of chicken stock
2.0 bouquet garni
2.0 salt and pepper