In a medium saucepan, combine milk, sugar, and vanilla extract. Heat over medium heat until it begins to steam, but do not boil.

In a separate bowl, whisk together eggs and semolina flour until smooth and no lumps remain.

Slowly pour about 1 cup of the hot milk into the egg mixture while whisking constantly to temper the eggs.

Pour the tempered egg mixture back into the saucepan with the remaining milk, whisking continuously.

Cook over medium-low heat, stirring constantly with a wooden spoon, until the custard thickens to a pudding-like consistency, about 8-10 minutes.

Remove from heat and stir in butter until melted and fully incorporated. Transfer custard to a bowl, cover surface with plastic wrap to prevent skin formation, and let cool to room temperature.

Preheat oven to 350°F (175°C). Brush a 9x13 inch baking dish with melted butter.

Carefully unroll phyllo dough and keep covered with a damp towel to prevent drying. Place one sheet in the prepared pan, allowing edges to hang over sides. Brush lightly with melted butter.

Repeat with 5-6 more sheets, brushing each layer with butter.

Spread the cooled custard evenly over the phyllo layers.

Fold the overhanging phyllo edges over the custard. Layer 6-7 more phyllo sheets on top, brushing each with butter.

Tuck edges down into the pan or trim excess. Brush the top generously with butter.

Using a sharp knife, score the top layers into 8 rectangular portions, cutting only through the top phyllo layers, not all the way through.

Bake for 40-45 minutes until golden brown and crispy.

Remove from oven and immediately dust generously with powdered sugar and a light sprinkle of cinnamon.

Let cool for 10 minutes before cutting completely through and serving warm.