Preheat oven to 350 ° F.

• Melt butter in the microwave or in a small saucepan on the stove. Use some of the butter to grease a large cookie sheet.
• Begin by folding one sheet of dough at a time, back and forth, accordion-style, then add to the pan. Tuck sides in, if needed, to fit the pan. When you're done, fan out the sheets to cover the entire pan.
• Drizzle butter over the crinkled phyllo sheets or brush on with a pastry brush, then bake for 15 minutes.
• Meanwhile, prepare custard by whisking the eggs in a medium-bowl. Add milk, sugar, vanilla, and rose water and whisk to combine. Set aside until needed.
• Remove pan from the oven and pour custard mixture over the phyllo dough. Make sure it is evenly distributed.
• Place the baking tray back into the oven and bake for 30 minutes, or until the custard is set and the dough is golden brown.
• Meanwhile, toast pistachios for five minutes and rind into a fine texture, but not a powder. Mix in cardamom powder. Once the crinkle cake is done baking, remove from oven and sprinkle with ground nuts. Cool completely before slicing into squares.