In a bowl combine the tahini with the yoghurt, lemon juice and a pinch of salt and pepper until smooth.
Next, trim the top off the leek where the leaves split, then rinse the leek (see notes) and pat dry. Slice the leek into 1cm (1/4”) thick rings.
Drizzle a little oil in a frying pan on a medium heat and fry the sliced leeks for around 5 minutes on each side or until golden brown and tender.
Sprinkle the thyme leaves over the leeks, along with a pinch of salt and pepper.
Transfer the leeks from the frying pan onto a plate and set to one side.
Add the maple syrup, paprika and chilli flakes to the frying pan, then bring the mixture to a simmer for 1 minute. Remove the sauce from the heat.
To serve, spread the yoghurt mixture across the toasted bread, then top with the leeks. To finish, drizzle the hot maple sauce all over.