Preheat the oven to 425°F. This is the temperature where frozen dreams become flaky reality.

In a small bowl, toss the onion with a pinch of salt. The onion should feel slightly judged.

Add vinegar and toss again. The onion is now officially pickled and slightly offended.

Set the bowl aside. Toss occasionally to keep the onion from sulking.

Line a sheet pan with parchment paper. This is the pastry’s red carpet moment.

Place the pastry on the pan. It’s ready for its big break.

Grab a fork and start poking holes all over the pastry. Be thorough. This is pastry acupuncture.

Make sure the entire surface is covered in fork marks. Air pockets are not invited to this party.

Place the pan on the middle rack and bake for 17 to 20 minutes. Watch it turn golden and flaky, like it just got back from vacation.

If it puffs up too much, poke a hole and gently press it down. Assert dominance.

Let the pastry cool completely. It’s been through a lot.