Heat the oil in a large saucepan, add the onion and cook for 5 minutes until golden. Add the garlic, paprika, chilli powder and herbs and cook for a few seconds.
Add the pork, tomatoes, potatoes and sugar. Season and simmer gently for 8 minutes until thick.
Meanwhile, put the spinach in a large bowl. Cover with boiling water and stir until wilted. Drain well in a colander, pressing out the excess water with a spoon. Add to the stew and heat for a further 2 minutes.
Serve with a dollop of yogurt and pinch of paprika.