Preheat your oven to 180C/Fan 160C/Gas Mark 4. Peel and grate or crush the garlic. Stir it into the yogurt with a little salt and pepper. Pop to one side.
Trim and finely chop the spring onions. Slice the thick stalks off the spinach. Finely shred the leaves. Warm 2 tbsp cold water in a pan. Add the spring onions. Season them. Cook and stir for 4-5 mins till soft.
Add the spinach to the spring onions with 1 tsp of the sumach. Cook and stir for 5-6 mins till the spinach is wilted. Stir every so often. Tip into a colander. Press it to squeeze out any excess liquid.
Finely grate or pare the zest from the lemon. Juice it. Put to one side.
Warm 1 tbsp olive oil in a deep frying pan. Add the spinach. Stir in the lemon juice and zest. Transfer to a baking dish if your pan is not oven proof. Use your spoon to make 4 holes in the spinach.
Crack the eggs into the holes. Pop a lid on the pan or cover with foil. Place in the oven and cook for 5-7 mins till the yolks are set to your liking.
Serve the spinach and eggs with the garlicky yogurt. Sprinkle with ½ tsp sumach each.