Mix the yeast with a pinch of sugar and 2 tbsp lukewarm milk in a bowl. Sprinkle in a handful of the flour, then add the rest of the milk and leave to stand for 5 mins or until frothy.

Cut the bread into slices 1cm thick, then cut them crosswise into cubes.

To make the dough, sift the remaining flour into the bowl of a stand mixer along with a pinch of salt. Mix the egg yolk into the yeast mixture along with 200ml more water and add it to the flour. Mix using dough hooks to make a smooth, soft dough that is very slightly sticky.

Put the bread cubes in a sieve and shake out any crumbs, then add to the dough and work them into it by hand – the cooked bread will absorb the extra moisture and need to be regularly distributed through the dough. Return the dough to the bowl, dust lightly with flour, cover with a clean tea towel, and leave to rise somewhere warm for about 1 hr or until doubled in size. Fold the dough over in the bowl several times during rising. Dumplings made from well-risen dough retain their shape better.

Turn the risen dough onto a flour-dusted work surface, work it lightly and cut it into four equal-sized parts. Knead them each gradually to form four smooth balls. Roll the balls out one by one with your palms into equal-sized logs with a diameter of about 5cm. These logs will need to fit lengthways into your largest saucepan or ovenproof casserole dish – cut them into more pieces if you need to but the width should remain the same. Push the tips of the dumplings slightly inward at the ends so that the ends have the same diameter as the middle; this way the dumplings will cook evenly. Arrange the rolled-out dumplings on a floured baking sheet and cover with a tea towel so they don't dry out. Leave to rise for another 10-20 mins and turn them once so that they're not flat on one side.

Bring some water to the boil in a large saucepan and add salt. You can cook the dumplings at the same time or in batches, depending on the size of the pan – it's important that they can float freely in the water. Slide the dumplings into the boiling water, then turn down the heat and gently lift them off the bottom of the pan using a wooden spoon, if you need to. Simmer for 8 mins, carefully turning them several times during cooking. When you take the dumplings out, put them on a cooling rack and pierce them with a skewer along the length so that the steam comes out and they don't overcook. Cut into slices to serve. You can do this easily using a piece of strong cotton thread: slide it under the log, bring the ends up on each side, cross them over and pull. Serve the dumplings with stews and casseroles.