Celery and Potato Soup for 4

Scaled to serve 3

37.5 g of margarineheattosssimmer 30minblend
337.5 g of celerycut into 1.5cm pieces
206.2 g of potatoespeeled, cut into 2.5cm cubes
675.0 ml of chicken stock
0.8 bouquet garni
0.8 salt and pepper