Halloumi, lemon & caramelised onion pie

Name: Halloumi, lemon & caramelised onion pie
Cuisine: European, British
Ingredients: SERVES 6; FOR THE ONIONS; 2 tablespoons olive oil, plus a little extra for greasing; 6 white onions, thinly sliced; 1⁄4 teaspoon soft brown sugar; the juice of 1⁄2 unwaxed lemon; FOR THE VEGAN PIE; 320g ready-rolled shortcrust pastry (most brands are vegan unless ‘all-butter’ is stated on the packaging); 1⁄2 a 400g tin chickpeas, drained and half the liquid from the tin reserved; 1 teaspoon dried mint leaves from most of a small bunch of mint, picked and roughly chopped; 1 teaspoon Dijon mustard; 1 clove of garlic, grated; the zest of an unwaxed lemon; 200g block of vegan halloumi-style cheese (sometimes called ‘Mediterranean-style’); OR FOR THE HALLOUMI PIE; 320g ready-rolled shortcrust pastry; 3 organic eggs, beaten; 1 teaspoon dried mint leaves from most of a small; bunch of mint, picked and; roughly chopped; the zest of an unwaxed lemon 225g halloumi; 1 teaspoon sesame seeds; FOR THE GREEN OLIVE SALSA; 4 spring onions, white and green parts thinly sliced; 12 green olives, pitted leaves from a few sprigs of; mint (use the rest from; the bunch above); 1 teaspoon red wine vinegar 1⁄2 teaspoon honey or agave; TO SERVE; green salad (optional) red wine vinegar-dressed