Rinse the meat, pat dry and chop. Peel the onions and garlic and finely chop. Heat the oil in a Dutch oven and sear the meat in batches over high heat. Add the onions and the garlic and season with salt and pepper. Sprinkle the flour over the meat, sauté while stirring and pour in 1/4 liter (approximately 1 cup) water. Add the bay leaf, cover and simmer over low heat 1 hour.
Peel the potatoes and cook for 30 minutes in boiling salted water.
Wipe the kale, remove the stalk, cut into thin strips and add to the potatoes during the last 20 minutes of cooking.
Grease a pie dish (18 cm diameter)(approximately 7 inches) well.
Thaw the puff pastry, place the sheets on top of each other and roll out. Pour the meat mixture in the pie dish, cover with the dough and press down on the edges. Cut off the excess and cut into desired pattern (such as leaves or flowers). Cut out a small hole in the middle of the dough so that the hot air can escape. Brush the surface with beaten egg yolk and bake in an oven preheated to 180°C (approximately 350°F) convection for about 30 minutes or until golden brown.
Drain potatoes and kale, mix and mash with a potato masher. Season with salt and pepper and serve with the pie.