Method

• 1.
  For the dumplings, place the flour and salt flakes in the bowl of a stand mixer with the hook attachment and knead on low speed until combined. Increase speed to medium, add 130ml cold water and knead until well combined. Transfer onto a lightly floured work surface and knead until smooth. Set aside and cover with a clean tea towel for 20-30 minutes.
• 2.
  On a floured surface, divide dough into 4 pieces. Roll each piece into a log about 1.5cm thick (like a rope) then cut into 1cm pieces. Use your thumb to drag the dough towards you, making an indent. Repeat with remaining dough. Place on a tray and cover with a clean tea towel until needed.
• 3.
  Bring a large saucepan three-quarters full of salted water to the boil. Blanch dumplings for 3-4 minutes until they float. Drain and transfer to a bowl, and keep warm. Reserve about 150ml of blanching water.
• 4.
  Meanwhile, place toum (or garlic sauce) in a large saucepan over medium heat. Gradually add reserved water and, using a whisk, stir constantly until combined. The sauce should be slightly thickened. Bring to a gentle simmer then add the dumplings and cook, stirring occasionally, for 2-3 minutes or until the dumplings are heated through. Season to taste and stir in lemon juice. Do not boil or the sauce will split.
• 5.
  Place the dumplings and toum sauce in a large bowl and sprinkle with sumac. Scatter over watercress to serve.