Add blackberries, water, and sugar to a pot. Bring to a boil, then reduce heat and let boil for 5 minutes. Taste and add more sugar if needed.
In a bowl, add flour. Pour in a small splash of oil and slowly add milk until a biscuit-like dough forms. This is a spponable, looser dough, like Mum's kładzione kluski.
Spoon the dough into the boiling berry mixture until you’ve used all the dough or filled the pot.
Turn heat to low, cover with a lid, and simmer for 5 minutes. Don’t stir - just gently shake the pot if needed.
Check a dumpling to make sure it’s done, then serve and enjoy!
