Mix yogurt, tahini, lemon juice, minced garlic, salt and chopped parsley together in a bowl. Cover and keep in the fridge until needed.
Make the homemade pita
Put the flour, sugar, yeast and salt in a bowl (or your stand mixer fitted with the dough hook).
Add the water, yogurt and olive oil. Mix together with a spoon and once the dough comes together use your hands to lightly knead in the bowl until well combined. Cover the bowl and leave the dough to rise for an hour – it won’t rise significantly.
Tip the dough onto a well-floured tabletop. Briefly knead and form into a log. Cut into six equal portions. Keep any dough you are not using covered with a damp cloth.
Roll each portion out, adding more flour if the dough is sticky. Keep the pitas separated by greaseproof paper and covered with a damp cloth once rolled out.
Heat a large non-stick frying pan and wipe with a little olive oil. Cook the pita over high heat, for a couple of minutes per side until nicely coloured. Keep warm or pan fry/grill to reheat before serving.
Preparing and cooking the lamb
Mix oregano, sweet paprika, garlic granules, salt and pepper together in a bowl. Rub this seasoning all over your shoulder of lamb. Add olive oil and vinegar and coat the lamb. Cover and marinate for at least an hour.
Preheat the oven to 170C / 325 F. Set a shelf on the lower third of the oven.
Cook the lamb for an hour covered with foil. Remove the foil and cook for a further 20 minutes. Cover loosely with foil and leave to rest for 30 minutes. The lamb is cooked when the internal temperature is 70°C (158°F) for medium-well done.
Slice the lamb thinly, removing any fatty bits. Add a few tablespoons of the pan juices to the sliced lamb. Keep warm.
Make the gyros pita
Finely slice one red onion and mix with generous amount of chopped parsley. Finely slice two large tomatoes, discarding the seeds.
Spread your warm pita with the yogurt sauce. Add a generous amount of lamb and then top with the tomatoes and onions. Wrap the pita around the fillings and eat immediately!
Video
Notes
Make the yogurt sauce first as it can be chilling in the fridge while you get on with the rest. Start marinating the lamb (1h) then cook (1 h 20m). When lamb goes in the oven starting making the pita (1h rising time) then roll out the pita and get it ready to pan fry. Lamb comes out of the oven and rests (30m) while you pan fry the pita. Slice the lamb, tomatoes and onion and you are ready to serve.
Recipe makes 6 pitas - enough for the amount of lamb specified. Double the recipe if making a 2 kg (4lb) whole lamb shoulder.