Custard:
In a saucepan, heat 7 cups of milk with the sugar, stirring until fully dissolved.

Dissolve the cornflour in the remaining 1 cup of milk and add it to the pot, along with the vanilla.

Beat the eggs and slowly add them to the mixture, stirring continuously.

Add the butter and orange zest.

Cook the cream over medium heat, stirring regularly until it thickens.

Once it starts to bubble, remove from the heat and let it cool completely before using.

Syrup:
In a pot, combine all the syrup ingredients, including the halved orange.

Bring to a boil and let it simmer for 15 minutes.

Remove from heat and allow the syrup to cool completely.

Assembling the Galaktoboureko:
Unroll the filo sheets, brushing each one with oil or melted butter, and layer them one by one into a 28cm round baking pan.

After laying 9–10 greased sheets, pour in the cooled custard and spread it evenly.

Fold the overhanging filo edges inward over the filling.

Place 2–3 more greased sheets over the top and tuck in the edges underneath the custard.

Score the top in radial slices, like a pie.

Baking & Finishing:
Bake in a preheated oven at 180°C (356°F) for about 45 minutes, or until golden and crisp on top.

Once baked, immediately pour the cold syrup evenly over the hot galaktoboureko. Allow it to absorb fully before serving.