In a large pot, heat a splash of oil over medium heat. Add diced onion and sliced mushrooms, stirring occasionally for about 10 minutes until softened.

Introduce the beef stew meat to the pot, browning it for about 5 minutes on all sides. Then, add chopped carrots, cubed potatoes, and the undrained stewed tomatoes.

Pour in enough beef broth and water to cover the ingredients. Bring the pot to a boil over medium-high heat, then reduce heat to low, cover and let it simmer for 1 hour and 15 minutes.

While the stew is simmering, prepare the dumplings by combining flour, baking powder, and salt. Stir in whole milk until the mixture is wet but slightly sticky.

Once the beef is tender, drop spoonfuls of the dumpling mixture over the simmering stew. Cover the pot and let the dumplings cook for an additional 10 minutes without lifting the lid.

After 10 minutes, check that the dumplings have risen beautifully. Ladle portions into bowls and serve hot.