Preheat the oven to 180C fan forced.
Mark and cut the shape of the frying pan onto the puff pastry before commencing cooking.
Place the butter into a frying pan that is suitable to go into the oven. Melt over a low/ medium heat, add garlic and herbs. Stir on low to ensure the butter doesn’t burn. Add brown sugar, pear syrup and whiskey. Stir to combine
Place the leeks into the pan, standing cut side up. Season with salt and leave to cook for 10 minutes to soften over a medium heat. Gently turn the leeks over with tongs half way through cooking to ensure they cook evenly.
Drop the philly cheese evenly over the shallots. Place the puff pastry over the leeks in the pan and tuck the pastry in at the sides.
Bake in the oven for 20 - 25 minutes or until pastry is lightly golden and cooked.
Allow Tarte to cool in the pan for 5 minutes or so. Place a large plate over the top of the pan and flip it over (using pot mits) to remove it from the pan. Garnish with fresh chives and parsley. Serve immediately.