Ingredients

1. 6 ounces spinach, stems removed and rinsed
2. 1 stick (4 ounces) unsalted butter
3. 2 3/4 cups finely chopped yellow onions
4. 1/4 cup finely chopped celery
5. 1 tablespoon minced garlic
6. 2 tablespoons Herbsaint or other anise-flavored liqueur, such as Pernod or Pastis
7. 1/2 teaspoon salt
8. 1/4 teaspoon freshly ground black pepper
9. 1/2 cup cracker meal or cracker crumbs
10. 5 drops green food coloring (optional)

Directions

1. Bring 1 quart of water to a boil in a medium pot. Add the spinach and cook until very tender and the water is green, 5 to 6 minutes. Drain the spinach in a colander set over a large bowl and reserve 2 3/4 cups of the cooking liquid. Let the spinach sit until cool enough to handle, then finely chop, and set aside.
2. Melt the butter in a medium pot over moderately high heat. When the butter is foamy, add the onions, celery and garlic and cook, stirring, until softened, about 3 minutes. Add the reserved spinach water, bring to a boil and cook for 1 minute. Add the chopped spinach, liqueur, salt and pepper and simmer, stirring occasionally, until the mixture reduces slightly, about 10 minutes. Remove from the heat, add the cracker meal and food coloring, and stir well to combine. Cool completely before using.

Make Ahead

The sauce can be refrigerated for up to 3 days.