Cover the frozen peas in a bowl with boiling water and let them steep for about 3 minutes. In the meantime clean, wash and chop the spring onions. Drain the peas. Crumble the feta roughly. Puree peas and feta, up to about 1 tbsp each for the topping, with spring onions, lemon juice and 2 tbsp olive oil using a hand blender. Mix in 2-4 tablespoons of water until the desired consistency is achieved. Sprinkle with pea feta topping.