A kolach, from the Czech and Slovak koláč, is a type of sweet bread that holds a portion of fruit surrounded by puffy yeast dough. Common filling flavors include tvaroh, fruit jam, poppy seeds, or povidla. In the United States, the word kolache is sometimes used as the singular rather than as the plural, and the letter "s" is often added to the end of the word kolache to form "kolaches", which is a double plural.