Start with the syrup so it can cool while you prepare the baklava. In a small saucepan, combine all the syrup ingredients (sugar, water, lemon juice, and lemon peel) and bring to a boil. Simmer until the syrup thickens.

The syrup is ready when a drop or two placed on the edge of a small plate stays in place for 1-2 seconds without running. When it reaches this stage, remove from heat and let it cool.

Place the almonds and walnuts in a blender or food processor and pulse until coarsely ground (they should still have some texture). Add the cinnamon and sugar and mix well.

Melt the butter in a small saucepan.

Begin layering the phyllo sheets, dividing them into two equal parts. Lay the first sheet so that half hangs over the edge of the baking dish (such as a 9x13-inch glass baking dish) and the other half covers the bottom. Generously brush the surface with melted butter. Lay another sheet from the opposite side, and continue. Fold the remaining sheets from the first half in half and place them inside the dish, brushing each with melted butter.

Once the first half of the phyllo sheets are used, spread the ground nut mixture evenly over the top.

Fold the overhanging phyllo sheets over the filling to seal it, brushing generously with butter. Continue layering the second half of the phyllo sheets, always folding them in half.

Place the final sheet on top and brush the entire surface with butter. Using a sharp knife, cut the baklava into small diagonal pieces. If you have any butter left, pour it over the top to cover evenly. The baklava is now ready to bake.

Preheat the oven to 285°F (140°C) with convection, and bake for 90 minutes. For the first 30 minutes, cover the baklava with a piece of aluminum foil to prevent it from browning too quickly. After 90 minutes, lower the temperature to 250°F (120°C), still with convection, and bake for another 60 minutes, again covered with foil. Remove the baklava from the oven and, while it is still hot, pour the cooled syrup evenly over the top. It's important that the syrup is cold and the baklava is just out of the oven. The baklava is ready! Let it cool completely before serving, and be careful not to let it crystallize. The flavor and aroma are truly unique. Enjoy!