To make the chilli oil, pour oil into a small bowl. Grate garlic cloves using a microplane or fine grater into the oil. Split the chilli down one side, leaving it whole. Scrape out the seeds, throwing away the bitter pith, and place seeds in the oil. Using a muddler or pestle, bruise the chilli to release the flavours, and place in the oil, with a pinch of sea salt. Place to the side.
To make the langos, mix flour and salt in a large bowl. Dissolve yeast in the warm water (make sure it’s not too hot or you’ll kill the yeast) and leave for 10 minutes, until it starts to bubble.
Make a well in the centre of the flour and add the yeast. Using your hands, work the dough until it’s smooth and doesn’t stick. Add a little more flour if necessary. Cover bowl with a clean cloth and leave for 40 minutes, for dough to rise to approximately double its size.
Tip the dough onto a floured surface, and carefully stretch it out as evenly as you can, until it’s about 1cm thick. Using a large cookie cutter or glass (about 10cm width), cut out round shapes. Use your hands to stretch your langos to make them thinner in the middle, and thicker around the edges, to hold the toppings. Repeat until you’ve used all the dough, cover langos with a clean cloth and leave on the floured surface for another 30 minutes.
Preheat oven to 200°. Place tomatoes in a roasting dish or ovenproof pan with 2 spoonfuls of the chilli oil and a drizzle of balsamic vinegar, and cook until skins blister and burst, around 15 minutes.
Heat about 1cm of vegetable oil in a large, heavy-based frying pan. Turn heat to medium, and place langos in the hot oil, making sure they don’t touch each other. Fry on one side until golden, then turn, cooking until the breads sound hollow.
When langos are ready, transfer to a plate and top with the blistered tomatoes, spooning any pan oil on too. Top with olives, crumbled feta and basil leaves, and finish with a drizzle of the chilli garlic oil.
TIP: The garlic chilli oil will keep if stored in a sterilized, airtight bottle.