Wash the nettles and wild garlic thoroughly with plenty of cold water.
Bring a pot of water to the boil, add the nettles and blanch them for 2-3 minutes.
Reserve 250 ml (1 cup) of the nettle water, and remove the rest.
Squeeze out the excess water, and chop the nettles finely.
In a pan set over a medium heat, melt the butter, and the peeled and chopped onion with a pinch of salt, and fry it until golden.
Add the flour, and stir well, then add the chopped nettles and wild garlic, and give it another good stir.
Pour in the reserved nettle water, and mix well to get a creamy, thick texture.
To make the polenta, bring the water to the boil, add the salt, then gradually whisk in the corn flour.
Continue to cook on a medium heat, whisking frequently, until the polenta is creamy and it pulls away from the sides of the pan.
Once the polenta is ready, transfer it to a plate, and top it with creamy nettles and a fried egg.