In a large pot over medium heat, combine canned tomatoes with vegetable stock. Stir well and bring to a gentle simmer for about 10 minutes.

In a mixing bowl, whisk together all-purpose flour, baking powder, salt, and pepper. Gradually fold in milk and melted butter until just combined. Mix in shredded cheddar cheese gently.

Once the soup base is simmering, adjust seasoning if necessary and let it cook for another 5 minutes.

Drop spoonfuls of dumpling dough into the simmering soup, cover tightly, and cook for 10-12 minutes without lifting the lid.

Ladle soup into bowls, garnish with extra cheese or herbs if desired, and serve hot.