Melt 1 Tbsp of butter in a pan over medium-high heat. Add the shallots and sauté until translucent, about 1 minute.
Pour in the wine and scrape the pan bottom to loosen any browned bits.
Add the stock, tarragon and the red currant jelly and cook, stirring, until the mixture is reduced to about 1 1/2 cups.
Stir in the demi-glace, the remaining Tbsp of butter, and the currants, and cook just until the butter melts and a smooth sauce has formed, about a minute longer.
Sprinkle with salt and pepper and serve over filet mignon or beef tenderloin. Serve the remaining sauce at the table.