Make the gastrique by heating the white wine and white wine vinegar in a saucepan, together with the crushed peppercorns, sliced shallots, and bay leaf.
Reduce to 1/3.
Pass through a fine sieve.
Add the Culinaire Original.
Reduce to the desired thickness.
Reduce to the desired thickness.
Add the butter for an extra full and rich flavour.
Cool the base sauce and store in the refrigerator or freeze.