Dissolve the corn starch
in a few tablespoons orange juice, heat the rest of the orange juice,
add the chicken stock, add the corn starch, stir until nice and thick.
Put the heat off, stir in the campari and add slowly the butter, while
beating with a whisker.
Fry the onions in the butter for ten minutes on very
low heat. Add the wine, cook on high fire until liquid is reduced to
half, add the stock, again reduce, to half add the cream and cook until
the sauce is nice and thick. Add oregano and mustard. Serve with beef