In a small stainless steel saucepan place the 3 cups of Merlot and 2 Tbsp. minced shallots.
Boil the wine with the shallots until it has reduced to thick sticky paste. Be careful not to burn the wine.
Add cream and return to a boil. Continue boiling until it is reduced by half.
Cut the butter into small 1/2 oz. cubes.
Over a low flame add the butter cubes to the sauce 1 at a time while continually whisking the sauce. If the sauce gets too hot and starts to separate add another butter cube to cool it down. If the sauce starts cool down and get thick wait a while before adding another cube and let it heat up.
The trick is to not let the sauce get too hot or too cold or it will break. You want to keep it between 100° - 120°.