Heat the olive oil in a frying pan and fry the onions for 4 minutes on a medium heat.
Peel and crush the garlic and add to the onions with the cinnamon, sugar, salt and pepper and fry for another 3 minutes.
Add the chopped dill, tomato puree and 4 tablespoons of water and continue to fry for another 3 minutes until the onions are completely soft. Take off the heat and set aside.
Finely chop the dates and fold into the onion mix. Roughly chop the walnuts.
Heat the oven to 180°C fan.
Cut the filo pastry sheets in half. Place one sheet into a buttered 24x18cm roasting tin and brush with melted butter. Repeat with three more filo pastry sheets, arranging them in layers.
Top the filo with half the onion mix, scatter with half of the walnuts, then crumble in half of the feta.
Add another four layers of buttered filo pastry sheets followed by the remaining onion mix, walnuts and feta. Finish with four layers of buttered filo pastry.
Before baking the baklava, cut it into squares. Make sure to cut all the way down through the bottom layer, so the filo doesn’t break when you cut it again after baking. Sprinkle with black sesame seeds, if using.
Bake for 35 minutes in the preheated oven.
Drizzle the warm baklava with a tablespoon of melted honey before serving.