In a small bowl, mix together 1 tablespoon each of flour, yeast and honey or sugar. Add the lukewarm milk or water (no warmer than 40°C) and whisk together. Leave to stand in a warm place for 10 to 15 minutes, until the mixture begins to foam.
In a large bowl, beat the eggs and salt. Add the oil or melted butter and beat a little more. Stir in the yeast mixture. Add the rest of the flour in parts, mixing and kneading as you go, until the dough is soft and elastic. Shape the dough into a ball and transfer to a greased bowl. Cover and leave to rise in a warm, dry place for at least an hour or until the dough doubles in size.
In the meanwhile, prepare the potato filling. Boil the potatoes in a large pot of water. When they have cooled slightly, peel and mash. In a large pan, heat the oil or butter and fry the onions until they are soft and transparent, but not browned. Remove the pan from the heat and mix in the mashed potatoes. Season with salt, pepper and nutmeg.
Preheat the oven to 180°C. Line two baking trays with parchment paper.
Place the dough on a wooden board and knead a little, then roll it out into a sheet about 0,5cm thick. Using a plate with a diameter of about 10cm as a template, cut out as many circles as you can. Place a spoonful of filling in the centre of each circle. Dampen the edges of the dough with a few drops of cold water and fold each circle in half. Crimp the edges together with your fingers to seal. Arrange the knishes on the baking trays and cover with a clean cloth. Leave to rise in a warm spot for about 30 minutes.
Brush each knish with beaten egg and sprinkle with poppy seeds. Bake for 20 to 30 minutes or until brown. Serve warm or at room temperature.
This recipe is from the book A Taste of Israel: From Classic Litvak to modern Israeli by Nida Degutienė, published in 2015 by Struik Lifestyle. For more information on the book, click here.