While the cake is chilling, prepare the filo pastry by cutting each sheet into a round circle the same size as your cake pan.
3 filo pastry sheets
Make the nut filling: Place the pistachios, walnuts, cinnamon, and salt in a food processor and blend until they form small crumbs. Don’t blend them to a powder, keep them roughly chopped.
50 grams pistachios, 50 grams walnuts, 1 tsp cinnamon powder
Layer the filo pastry: Place one sheet of filo on top of the cake batter, then brush it generously with melted butter. Make sure all the corners are covered in butter. Add 2-3 spoons of the nut filling on top of the butter and evenly spread it across the filo pastry, leaving a little space on the edges. Place the second layer of filo pastry on top and repeat the process. Finish with another layer of filo brushed with melted butter.
200 grams butter
Bake the cake for 40-45 minutes until the cake is fully cooked. At the end of the baking time, turn on the top broiler of the oven and cook until the filo pastry becomes golden brown. Keep an eye as it can burn easily. The top filo might curl up in process but don't worry, you can shatter it to create a fun effect.
Make the sugar syrup: While the cake is baking, make the sugar syrup. Add the water and sugar in a saucepan, don’t mix it as that may cause crystallization. Let the syrup cook on high heat until it starts boiling, then lower the heat and let it cook for 10 minutes until it thickens enough to coat the back of a spoon.
500 ml water, 350 ml granulated white sugar
As soon as the cake comes out of the oven, pour 3-4 tablespoons of sugar syrup on top of the baklava. Let the cake cool down completely before removing it from the pan.
If serving after. a few hours, place the cake under the broiler for 3-5 minutes to crisper the filo pastry sheets.