Heat remaining butter in a 6-qt. saucepan over medium-high heat; add paprika and onion, and cook, stirring, until soft, about 5 minutes. Add vegetable stock, cauliflower, and carrot; season with salt and pepper, and bring to a boil. Reduce heat to medium, and cook, stirring occasionally, until vegetables are tender, about 15 minutes. Using a ½-tsp. measuring spoon, portion out and drop all dumpling dough into simmering soup; cook, stirring occasionally, until dumplings are cooked through, about 3 minutes.