In a separate bowl, whisk 1 cup of the hot milk mixture with the beaten eggs, adding the hot milk mixture in a thin steady stream while whisking. Pour the egg mixture into the saucepan and whisk constantly until it thickens a bit more, about another 3 to 5 minutes. (It should be thick enough to support the weight of the filo dough spiral we'll make without the filo dough sinking into the custard.) Remove from heat and stir in the lemon juice, lemon zest, vanilla extract, cinnamon, and chopped peach until combined. Set aside.
Take one sheet of filo and lay it out on the work surface and brush it lightly with the melted butter. Take another sheet of filo and place it on top of the first and brush it lightly with butter. You should have two sheets layered on top of each other lightly brushed with butter. Scrunch up the filo length-wise to create a long ridged piece of filo. Now place the end of this filo at the end of the first piece, and twist it around the original spiral to continue the spiral shape outwards. You should have a round spiral of filo measuring about 8 inches across. Pick this up and place/nestle it on top of the custard in the pan (it helps if you have a large pancake spatula or plate you can use to slide the spiral off of and onto the top of the custard).