Preheat the oven to 400° F / 205° C. Line a half-sheet rimmed baking tray with parchment.

In a small bowl, whisk together the goat cheese, lemon juice, and lemon zest. Season with salt and pepper, to taste.

Unroll puff pastry and trim to approximately 9 x 12 inches. (If your pastry sheet is a square instead of a rectangle, use a rolling pin to roll it a few inches longer.) Place on prepared tray.

Spread with the goat cheese mixture, allowing a 1-inch border around the edges.

Arrange the asparagus in a straight line on top of the goat cheese.

With a pastry brush, apply a thin layer of beaten egg along the pastry border.

Turn up the edges, gently wrapping the pastry around the ends of the asparagus.

Crimp with a fork.

Brush the crimped edges with more of the beaten egg.

Sprinkle with the grated Parmesan.

Sprinkle with chili flakes (if using) and season with salt and pepper.

Bake in preheated oven for 22 – 24 minutes, or until pastry is flaky and golden brown. Sprinkle with fresh thyme leaves. Serve warm.

Puff pastry tart is best served on the day it is made. Wrap leftovers in foil and store in the refrigerator for up to two days. Do not reheat.