Combine 1/4 tsp of ground saffron or saffron strands with 1 tbsp of freshly boiled water. Set it aside for later, preferably in a warm place.
Finely chop the onions and garlic.
Cut the meat in chunky about 3cm / 1″ large cubes.
Heat 20ml / 1/2 cup vegetable oil in a pan and fry the meat from all sides until golden brown. This should take about 15 minutes.
Remove the meat from the pan and gently fry the onions in the same oil over medium heat for about 5 minutes. Then add the chopped garlic and fry both together for another 3 minutes.
Transfer the meat back to the pan with the onions and garlic. Also add the golden sour prunes now. Boil 500ml / 2 cups of water in a kettle and add it to the pan. Season with 2 tsp turmeric, 1 tsp black pepper and 1/2 tsp of salt or as much as you like. Bring the stew to boil and once boiling, reduce the heat to medium, put on the lid and let it simmer for 1 hour.
Fry the spinach in 2 tbsp of vegetable oil for about 5 minutes.
The next step is optional but helps season your stew correctly and to preserve the whole prunes: Remove the meat chunks and prunes from the stew. The stew doesn’t have much sauce and therefore it’s easier to season it with lemon juice, sugar and saffron without the big meat chunks in the way. The prunes I remove, because I want them to remain whole and visible in the stew. I want to combine all the ingredients well and while stirring the softly cooked prunes are at risk of dissolving and disappearing in the stew.
Add the fried spinach to the stew, together with 3 tbsp lemon juice, 2 tsp sugar and the saffron water. You may need to add a little more freshly boiled water now, if the stew has become too dry. Combine everything well and return the meat and prunes to the stew, if you removed them before. Let the prune spinach stew simmer for another 20 minutes.
Serve your Khoresh-e Aloo Esfenaj with aromatic Persian rice and fresh herbs, yoghurt or red onions, if you like. Enjoy!