Mix sugar and yeast with warm milk, melted butter and oil. Place in mixing bowl, add salt and water, then begin to mix using a dough hook attachment, gradually adding in flour. Knead mixture well until you have a pliable, soft and non-sticky dough. Cover with a moist cloth and let it rest somewhere warm for 45 minutes; it should double in size.
For the meat filling, heat oil in a frying pan on a medium heat; add onion, garlic and salt and sauté until softened. Add lamb mince and spices and brown the meat. Stir through tomato paste then add the passata. Bring to a simmer and cook on a low heat until mixture is flavoursome and reduced (about 25 minutes). Make sure the mixture isn’t too wet or it will be difficult to roll the pastries. Check seasoning.
For the feta filling, mix together ingredients. Check seasoning.
Divide the dough mixture into 20 balls. Roll each ball into a disc shape. Place spoonfuls of feta mixture on 10 discs and close by folding the edges upwards like a bundle, into a ball shape. Repeat with meat filling on remaining discs. Make sure filling is completely enclosed in dough, then place on a lined baking tray with the folded side on the bottom. Rest somewhere warm for about 15-20 minutes.
Preheat oven to 180C.
Brush beaten yolk on top, sprinkle with nigella seeds and bake for about 20-30 minutes until golden.