Cut the butter into pieces and leave at room temperature to soften
Peel and chop the shallot
In a pan bring the red wine and the shallots to the boil and cook until the liquid evaporates
Then allow the sauce to sit for approximately 20 minutes
In a bowl, mix the softened butter together with the shallots and the remaining red wine
Roll into a cylindrical shape and wrap in clingfilm
Refrigerate for at least 1 hour before using.