1. Heat oven to 400 degrees F. Line two baking sheets with parchment paper. Toss together cheeses, garlic powder, red pepper (if using), and salt in a small bowl. Whisk together egg and water in a mug.
2. Unfold 1 pastry sheet onto a lightly floured surface. Roll to a 10x10-inch square. Brush pastry with egg wash. Sprinkle with half of cheese mix. Sprinkle with 1 tsp. poppy seeds. Press mixture into pastry. Cut pastry into nine to ten strips. Lay each strip on a baking sheet, and twist a few times. Chill baking sheet in fridge until ready to cook, and repeat with remaining pastry.
3. Bake, rotating pans once, until lightly browned and puffed, about 14 to 16 minutes. Cool completely.