Make a roux out of butter and flour and deglaze with a mixture of broth and milk. Simmer for approx. 5 - 10 minutes, stirring, so that the flour taste disappears. If desired, dilute with milk until the desired consistency is achieved.
Stir in the grainy mustard and cream cheese. Season everything with salt, pepper, nutmeg and agave syrup.
This sauce tastes good not only with the well-known mustards, but also with grilled meat.