It's important to get children out foraging so that they appreciate that not everything we eat has to be bought from the shops. Food for free is a great motivating device, whether it be for mushrooms, berries or sea vegetables.
If you're struggling to find sea spinach, then you could improvise with a selection of spring vegetables, or even some baby spinach leaves, chard, cultivated sea kale, imported samphire, etc – though these tend to be a lot more expensive.
500-600g sea spinach, stalks removed, washed and dried
200ml double cream
Salt and freshly ground black pepper
4 slices of bloomer loaf
4 hens' eggs
Cook the sea spinach or vegetables in boiling salted water for 3-4 minutes until tender, then drain and squeeze out as much water as possible, reserving a little to help blending.
Coarsely blend in a food processor then transfer to a saucepan. Add the cream, season and simmer until the mixture is thick, re-season if necessary. Toast the bread on both sides and poach the eggs.
To serve, spoon the creamed sea spinach on the toast; place the egg on top.