This white sauce is exceptionally delicious, combining sweet and sour flavors enhanced by the aromatic taste of fresh dill. Koprová omáčka is a traditional Czech recipe that I highly recommend to anyone interested in Czech cuisine.
Make roux: Melt ½ stick unsalted butter over medium heat in a thick-bottomed pot (I use my Dutch oven). Add 3 Tablespoons all-purpose flour and stir well for 1 minute, until the flour starts bubbling and turns a light golden color.
Gradually add 3 cups vegetable broth in batches. Begin by adding about ½ cup while stirring, creating a thick floury mash. Continue adding broth and stirring until all the broth is incorporated. This method of making a roux-thickened sauce will prevent lumps from forming.
Bring the sauce to a boil, then reduce the heat to a minimum. Cover with a lid and let it simmer for 20 minutes.
Add 1 teaspoon salt, 3 Tablespoons granulated sugar, and ¾ cup heavy cream to the sauce. Stir well, then set aside without cooking any further.
Add 2 Tablespoons vinegar and 3 Tablespoons fresh dill leaves, then mix well. Adjust the seasoning with more salt or sugar to taste, if necessary.
Let it sit for 5 minutes, and Koprová omáčka is ready to serve!
Notes
The basic recipe makes 3 servings.
Serve warm with sliced bread dumplings arranged along the edge of a plate. Pour Koprovka into the middle of the plate, allowing some of the sauce to partially cover the dumplings. Place a halved hard-boiled egg, yellow side up, in the sauce and garnish with a sprig of fresh dill.
Koprovka is a white sauce, so the roux you make at the beginning should only be lightly golden, not brown. Fry the roux for a maximum of 1 minute.
For the best flavor, add the dill only at the end of cooking. Fresh dill loses its flavor and vivid color the longer it is cooked.