Sift the flour, bicarb and salt into a large bowl.

Stir in the yoghurt and then the cooled butter, and mix until you have a smooth, damp but not too sticky dough.

Cover and leave to rest for 30 minutes - it won't rise, but this will make it easier to roll out.

Meanwhile, grate the cheeses - with the Port Salut (or similar), it will be easiest to do this if it's cold from the fridge, though it will still be less amenable than the halloumi.

Combine the grated cheeses and season lightly, if you wish.

If you're planning to bake the khachapuri in the oven, heat it, and a lightly greased baking tray, to 220C (200C fan)/425F/gas mark 7.

Roll out the rested dough on a very lightly floured surface to a roughly 0.5 cm-thick circle.

Pile the grated cheeses in the centre, leaving a wide border all around the edge, bring two opposite points of the circle together in the centre over and across the cheese, then pinch together.

Repeat, bringing together more of the edges of the circle, until you end up with a large, firmly sealed cheese dumpling.

Lightly flatten this to about 25-30 cm in diameter, first with your hands and then a rolling pin.

If you're baking the khachapuri, cut a small air hole in the top.

To bake, slide on to the hot greased tray and put in the oven for about 15 minutes, until golden brown.

If cooking it in a pan, put a frying pan on a medium heat, then add the bread and leave to cook for about five minutes, until brown spots appear on the base.

Carefully flip over (a plate will help here) and repeat on the other side.

If the khachapuri begins to bulge, cut a small hole in the top to let out steam, but don't do this until after you flip it or the cheese will begin to leak out.

Paint the top and sides with melted butter and serve hot.