In a saucepan bring red wine or brandy to boil then add the crushed peppercorn and salt.
Reduce the liquid on low heat until it thickens. It takes about 1 - 3 minutes.
Stir in the milk and the cream.
Bring it to boil and simmer away a bit of liquid if a thicker sauce is needed or replace part of the milk with cream.
Advanced
Add red wine or brandy with crushed peppercorn and salt into a saucepan then reduce the liquid to get a thick sauce.
Melt butter in a saucepan on medium heat then gradually incorporate the flour.
Once all the flour is added we get clumps of buttery flour.
Start incorporating the milk slowly while stirring continuously. Heating up the milk beforehand may speed up the process.
Continue stirring it until we get the desired thickness. Take it off heat and stir until all the lumps are broken up and we have a nice smooth bechamel sauce.
Mix bechamel into the peppercorn sauce.
Overkill
Melt butter in a saucepan and saute onion with salt on medium heat until it gets a glassy / translucent look for about 1 -3 minutes.
Mix in garlic and black pepper then saute until garlic gets fragrant for about 1 - 2 minutes.
Pour in red wine or brandy then add bay leaf and thyme.
Reduce the liquid to at least half for about 2 -4 minutes.