Holding each asparagus lightly, snap in two and discard the woody ends.
Toss asparagus in a splash of olive oil and sprinkle with lemon zest. Mix to coat.
Roll out and pat each sheet of puff pastry directly on a silpat pan liner or a piece of parchment paper until it is about an 11” x 14” rectangle. Take a fork and poke holes all over the pastry, leaving a one-inch border all around.
Within that border, sprinkle half of the Boursin cheese on each puff pastry sheet. Then sprinkle each with 1/2 cup Gruyère cheese.
Take out the asparagus and lay them vertically on top of the bed of cheese.
In a small bowl, whisk the egg with a drizzle of water to make a wash. Brush this egg mixture on the border of the pastry.
Bake for about 20 minutes or until the puff pastry has risen and lightly browned.
Cool slightly and sprinkle basil leaves on top.
Serve warm or at room temperature. Fresh lemon juice may be lightly squeezed over the tart.
Recipe by Just a Smidgen at https://justasmidgen.com/2012/03/16/a-palate-for-pleasure/