Grease a 9x13 inch pan generously with butter. Preheat oven to 200 degrees.
Take two sheets of the phyllo pastry sheet and crinkle it. Place in the pan facing the crinkles on the top.
Place them tightly to make sure that all the phyllo sheet is accomodated in the pan.
Bake for 10 minutes.
Take out and pour melted butter all over the phyllo. Bake for 10 minutes.
Meanwhile, whisk together eggs, milk, sugar and vanilla. Beat well till nicely combined.
Pour the custard mixture onto the semi baked phyllo. Return it back to the oven for another 30-40 minutes, till the phyllo is crisp on the top. (refer notes)
During this time, prepare the sugar syrup by combining the sugar and water in a saucepan and cook till the syrup thickens. Add the lemon juice and rose water if using and switch off.
As soon as the phyllo cake cames out of the oven, pour all the sugar syrup over the phyllo custard. Allow it to sit for sometime.
Enjoy it warm.