Combine the yoghurt and garlic in a bowl and season to taste with salt and pepper.

Bring a large pan of water to the boil over a high heat. Reduce the heat to low and add the vinegar and a pinch of salt. Stir the water rapidly in one direction to create a whirlpool effect. One by one, break the eggs into a cup and slide them into the water (gently tip the cup near the water's surface).

Place a large dollop of garlicky yoghurt in the centre of each of 4 plates. Spread it out, making a well in the middle for an egg. When the eggs are cooked to your liking (3 minutes for a soft yolk), remove with a slotted spoon and drain on kitchen towel. Place an egg in the middle of each plate. Season with salt and pepper and sprinkle with chilli flakes.

Heat a frying pan over a medium-high heat. Cook the butter and sage for about 2 minutes until the butter turns nut brown and the sage is crisp.

To serve, spoon the butter and sage leaves over the yoghurt and eggs.