Preheat your oven to 400 degrees.

On a lightly floured work surface, roll out your defrosted puff pastry to the size you want.

Prepare a parchment paper-lined baking sheet and place the puff pastry sheet on it.

Using a sharp knife, lightly score the pastry dough about 1 inch in from the edges to mark a rectangle.

Use a fork to pierce the dough in the center area, avoiding the edges.

Bake the pastry shell for about 12 to 15 minutes, until lightly golden.

Once removed from the oven, let the pastry sit for a minute. Spread the honey dijon mustard over the surface, then sprinkle the Gruyère cheese on top.

If the puff pastry puffs up too much, poke some holes in the center to let the air escape and gently press down the center to flatten while keeping the edges puffy.

Trim the bottoms of the asparagus spears and arrange them in a single layer over the Gruyère cheese, alternating ends and tips.

Brush or drizzle with olive oil and season with salt and pepper.

Place the tart back in the oven and bake for about 20 to 25 minutes, or until the asparagus is tender.

Once finished, let the tart cool for a few minutes. Add lemon zest and a drizzle of balsamic glaze if desired. Slice, serve, and enjoy!