In a 1-quart saucepan combine the stock and garlic. Bring to a boil over high heat, then reduce heat and simmer 2 minutes. Remove from heat.

In a 1-quart saucepan melt 4 tablespoons of the butter over high heat. Add the flour and whisk with a metal whisk until smooth, about 10 seconds. Remove from heat.

Return stock mixture to a medium heat. Gradually add the butter mixture to the stock mixture, whisking constantly until smooth. Reduce heat to very low.

Add the remaining 2½ sticks of butter, about a third at a time, whisking constantly each time until butter is melted.

Gradually add the Worcestershire, whisking constantly, and add the salt.

Continue cooking until sauce thickens slightly, about 5 minutes, whisking often.

The sauce may be kept warm (or reheated) by setting the pan over another pan of hot (but not boiling) water.