Preheat the oven to 180°C, gas mark 4. Put the rice in an ovenproof dish with the butter and water or stock. Stir well and cover with foil. Bake for 30-35 minutes until the rice is tender and has absorbed the water.
Remove from the heat, discard the foil and increase the oven temperature to 220°C, gas mark 8. Crumble in the feta with the dates. Season and mix well.
Bake for 10 minutes more until the rice and feta are brown and crisp around the edges.
Stir in the spinach and leave to wilt for a few minutes. Meanwhile, mix the pomegranate molasses and olive oil in a small bowl. Serve with the baked rice.