1 tblsp of butter
1 tblsp of flour
15cl of milk.
In a saucepan, melt butter over low to moderate heat. Add flour, stir from time to time. The mixture has to turn to a slightly golden color.
Remove from heat. Add half of the milk, stir vigorously. Add the other half of the milk and the bay leaf. Season with salt and pepper.Cover and cook over low heat for 3 minutes, stir every 20 or 30 seconds.