Start with the wine reduction. Melt half the butter in a pan and sauté finely chopped shallot until golden. Add the wine and salt, and cook over high heat for a few minutes. Add the remaining butter and flour, then let it reduce by two-thirds. Strain the sauce.

For the chocolate sauce: Melt the chocolate with the butter in a double boiler, stirring, and slowly add the Marsala wine. Let it thicken at room temperature.

Mix the ground coffee with the sugar and coat the edges of the beef tenderloin with this mixture.

Cook the tenderloin in a pan with a pat of butter for 2 minutes on each side. Let it rest covered with aluminum foil for a few minutes.