For the chicken w/ creamy dijon mustard sauce on this blog - have no cognac. Can I have 3 replacement suggestions?

You could try thinning out some apricot jam with some vodka.

Suggestions won't do you any good unless you already have the alternates on hand. We already know you don't have cognac. What do you have? Otherwise it's a trip to the liquor store.

Dry sherry will work, but will give a different flavor, as will marsala.

2) brandy

1) armagnac!