One 14-ounce package all-butter puff pastry, thawed if frozen but still cold
1 egg beaten with 1 1/2 teaspoons of water
In a bowl, mix the sesame, poppy, caraway, onion, salt and garlic powder.
Line 3 large baking sheets with parchment paper. On a floured surface, roll out the puff pastry into an 11-by-14-inch rectangle; cut in half lengthwise. Brush with the egg wash and sprinkle evenly with the seed mixture. Cut the pastry crosswise into 3/4-inch-thick strips. Twist the strips and transfer to the baking sheets, leaving 2 inches in between. Freeze until firm, 30 minutes.
Preheat the oven to 375°. Bake the twists for 22 minutes, until golden. Switch the pans top to bottom and back to front halfway through baking, until golden. Let stand until cool enough to handle, about 10 minutes. Transfer to a platter and serve.
The unbaked twists can be stored between layers of parchment paper and frozen for up to 1 month.