If possible, make the syrup the day before and leave in the refrigerator. Put the sugar, lemon zest, lemon juice, and water in a small saucepan. Set over a medium heat and stir occasionally until the sugar has dissolved. Lower the heat and simmer gently until it forms a thin syrup. This should take about 20 minutes. Remove from heat, then add Frangelico and Goldslauger and cool, but DO NOT strain. Chill when cooled.
Preheat oven to 325 degrees. Liberally butter a 2” deep 14” x 10” glass sheet cake pan.
Mix Macadamia nuts and sugar, and set aside.
Unwrap thawed filo pastry. Brush the first sheet with lots of butter and spread over the base of your pan. Continue to layer the sheets (lightly buttering between each sheet) until you have about seven layers. Then scatter them with one third of the Macadamia nuts. Cover with five more layers of pastry (again lightly buttering between each sheet), and then sprinkle half the remaining Macadamia nuts before covering with another five layers of pastry (don’t forget to butter lightly between each sheet). Scatter with remaining Macadamia nuts then top with remaining filo pastry layers. Liberally brush the top with melted butter.
With a sharp knife, gently cut through the top layers of pastry to mark out about 16 squares, diamonds or rectangles. Do not cut all the way through! Scores will help guide you when cutting and serving the finished product.
Put baklava in the oven and bake for 30 minutes, then increase the temperature to 375 degrees and bake for 10 minutes. It is ready when it looks golden and cooked through.
Meanwhile, strain the lemon zest and cinnamon sticks from the syrup. As soon as you remove the baklava from the oven, quickly pour the cold syrup evenly over all the baklava. Leave to cool. Cover and refrigerate. When cold, cut the pieces along the scores you made earlier. Baklava improves and becomes more “ooey gooey good” if served after being allowed to chill for a few days.