In a medium skillet, melt 2 tbsp of the butter over medium heat. Stir in shallots and cook 2 to 3 minutes, until softened. Stir in flour; cook 1 minute. Whisk in stock, wine and thyme. Bring to a boil. Reduce by half and simmer 10 minutes, until thickened. Remove from heat and stir in remaining 1 tbsp butter, the salt and freshly cracked pepper.