Bougatsa (Greek Custard Pie)

For the filling

1. In a medium bowl, whisk together eggs, sugar and semolina flour until well incorporated, about 1-2 minutes.
2. In a medium pot over medium heat add the milk and vanilla extract, whisk and then heat until hot to the touch, about 4-5 minutes (do not boil). Remove from heat.
3. Remove ⅓ cup of the hot milk mixture from the pot and slowly pour into the egg-sugar-flour mixture, stirring constantly to combine as you pour the hot milk in.
4. Put the pot back on medium / medium-low heat and pour the egg-sugar-flour-milk mixture into the pot, whisking constantly until the mixture has thickened and is smooth and creamy and coats the back of a spoon. Do not remove the pan from the stove while whisking. This should take 5-10 minutes.
5. Remove the pot from the heat, whisk in the salt and cubes of butter to fully combine and no lumps remain and then whisk in the orange zest. Set aside to cool while you make the phyllo crust *NOTE: whisk or stir the custard every few minutes to avoid a custard skin forming on top*

For the pastry

1. Preheat the oven to 350F.
2. Generously grease the 9x13 pan with butter and line with parchment paper.
3. Keep the defrosted phyllo sheets (covered with a damp towel) beside the baking pan along with 1 cup melted butter and a pastry brush or spoon - now you’re ready to assemble.
4. Place one phyllo sheet in the baking pan and brush with melted butter. Repeat with 5 more sheets of phyllo, layering and buttering each sheet, for a total of 6 phyllo sheets.
5. Pour the custard filling into the baking dish and gently spread the custard filling evenly over the phyllo layers. Gently fold the overhanging phyllo over the custard layer (don’t worry if there’s some custard still showing)
6. Place one phyllo sheet on top of the filling and gently brush with melted butter. Repeat with 5 more sheets of phyllo, layering and buttering each sheet, for a total of 6 phyllo sheets.
7. Use a sharp knife to score the top layers of phyllo into 12 squares.
8. Bake for 25-35 minutes until the top is golden brown and crispy.  Once baked, remove from the oven and let cool for 10-15 minutes before dusting with icing sugar and cinnamon.
9. Slice along the scored lines and serve pieces warm.