Savoy Cabbage Soup With Buckwheat Dumplings

Ingredients

• 2 teaspoons whole caraway seeds
• 1 1/2 teaspoons whole coriander seeds
• 4 slices thick-cut bacon, small dice (about 7 ounces)
• 1 medium granny smith apple
• 1 medium yellow onion, small dice
• freshly ground black pepper
• 4 teaspoons stone-ground mustard
• 1 medium savoy cabbage (about 1 1/2 pounds), wilted or damaged leaves removed, cored, and thinly sliced
• 3/4 teaspoon kosher salt, plus more as needed
• 4 cups (1 quart) low-sodium chicken broth
• 3 cups water
• 1 1/4 cups all-purpose flour
• 3/4 cup buckwheat flour
• 2 teaspoons baking powder
• 2 teaspoons kosher salt
• 1 teaspoon freshly ground black pepper
• 1 cup milk (not nonfat)
• 2 tablespoons unsalted butter, melted and cooled slightly