Ok, seriously, you're preparing filet mignon but don't have time to make a proper sauce?
Uh, run to the store and buy some boar's head horseradish sauce? Don't cook it til you have more time?
This thread makes me unhappy.
Ok, if you have any red wine, try this:
6 tablespoons cold unsalted butter (or use salted, it don't matter)
1 onion, thinly sliced
1 tablespoon minced garlic
1 teaspoon dried oregano
1/4 cup tomato paste
2 1/2 cups dry red wine
melt 2 tablespoons of butter in a heavy large saucepan over medium-high heat. Add onions and saute until tender, about 5 minutes. Season with salt. Add garlic and oregano and saute until fragrant, about 30 seconds. Stir in some tomato paste and cook for 2 minutes, stirring constantly. Whisk in the wine. Simmer until the sauce reduces by half, stirring occasionally, about 10 minutes. Remove the skillet from the heat. Strain the sauce into a small bowl, pressing on the solids to extract as much liquid as possible. Discard the solids in the strainer and return the sauce to the saucepan and bring back to a slow simmer. Cut 4 tablespoons of butter into small 1/2-inch chunks and whisk in the sauce a little at a time. Season the sauce, to taste, with salt and pepper.