Heat 2 tbsp oil in your largest frying pan. Cook the aubergine slices for about 5 mins on each side until golden brown and soft – you’ll need to add more oil between batches. Remove from the pan and set aside.
Fry the onion in the remaining oil until soft, about 8 mins. Add the garlic and cook for another min or 2. Stir in the coriander, chopped tomatoes, molasses and some seasoning. Simmer for 15 mins until you have a thick, rich sauce. Stir in the mint leaves.
Heat a drizzle more oil in a pan and fry the halloumi slices for 2 mins on each side until golden brown. Set aside with the aubergine. Heat oven to 200C/180C fan/gas 6.
Roll out the pastry to a rectangle, 50 x 25cm, and cut into two squares (don’t worry about all the edges being neat at this stage). Place one on a baking sheet lined with parchment. Layer the tomato sauce, aubergine, halloumi and a scattering of pine nuts (in that order) onto the middle of the pastry, leaving a border around the edge, about 1.5cm. Keep layering until the ingredients have all been used up. Brush the edges with a little egg.
Roll the second sheet a little larger, then lift over the pie and press down the edges to seal. Neaten the edges with a knife, then brush the whole pie with more egg. Score fine lines over the top with your knife to decorate, making sure you don’t pierce the pastry. Cut a small cross in the centre of the pie and sprinkle with sesame seeds. Bake for 30-35 mins until golden brown.