Preheat and grind the pistachios

• Preheat the oven to 180 °C (350 °F).
• Grind the pistachios in a food processor until very finely chopped.

Melt the butter

• Melt the butter in a pot on the stove or in a bowl in the microwave.

Layer the first phyllo stack

• Butter the bottom of the baking pan or tray.
• Lay a third of the phyllo sheets in the bottom.
• Brush the top sheet with melted butter.
• Spread half of the ground pistachios over the phyllo in one even layer.

Build the middle and top layers

• Repeat with the second third of phyllo sheets, brush with butter and spread the remaining pistachios.
• Top with the last third of phyllo sheets.

Butter and cut the baklawa

• Pour the rest of the melted butter over the baklawa and tilt the pan carefully to spread it all over.
• Use a sharp knife to make straight cuts across the entire surface in both directions, creating a grid of even squares.

Bake

• Bake until golden brown, rotating the tray halfway through.

Soak in syrup and rest

• Remove the pan from the oven and immediately pour the cooled simple syrup evenly over the hot baklawa.
• Allow to cool at room temperature.

Garnish and serve

• Garnish with more crushed pistachios before serving.