Heat the oil in a large skillet or saucepan over medium-low heat. Add the shallots and cook until softened, about 5 minutes. Add the broth and vinegar. Increase heat to medium, bring to a simmer, and cook for 2 minutes. Remove from heat.
Add the butter to the skillet and swirl until melted. Season with the salt and pepper. Pour or spoon the sauce over cooked meat.
DELICIOUS!!!