Mustard Sauce

1 C. fish poaching liquid
1 C. half-and-half or light cream
1 to 2 tsp. grainy mustard (such as Grey
Poupon Country Dijon), to taste
2 to 3 green onions, finely chopped, including
some of the green tops
Salt and white pepper to taste

Combine the poaching liquid, cream and mustard in a small saucepan,
bring to a boil, and boil, stirring frequently,
until reduced by about half and thickened to desired consistency.
Stir in green onions and season to taste with salt and white pepper,
adding a bit more mustard if desired.
Pass at the table in a small pitcher to pour as desired over warm or room temperature fish servings.

Makes about 1 1/4 C. sauce.