Mix the water, sugar, yeast and 50g of flour thoroughly, then cover and allow to ferment for an hour in a warm place.
When the yeast mixture is frothy and active, melt the butter and mix with the yeast mixture and the remaining flour for 5 minutes on a slow setting in a mixer with a dough hook. The dough will become elastic and firm.
Allow the dough to rise in a warm place and under cover for an hour (or until it doubles in size).
Place the loin in a preheated pan with a little oil and seal until golden brown.
Add the butter and allow to foam until nutty brown in colour, then add the herbs and garlic and cook gently until the meat reaches a core temperature of 45°C. Allow to rest for at least 10 minutes.
Cut the dough into 6 large or 12 smaller evenly sized pieces, then roll them out to a thickness of 5-6mm on a well-floured surface.
To cook the naans, dust off any excess flour and dry fry in a hot, heavy-bottomed pan. After 3-4 minutes, they will begin to puff up. Turn them over and cook for another 3-4 minutes. Once cooked, place on a cooling wire so they don’t sweat.
Add in the spinach, chickpeas and Puy lentils and reheat the sauce.
Season to taste, then pour the curry into a wide serving bowl, slice the loin and scatter over the curry, topping off with the yoghurt and chopped coriander