Preheat the oven to 400ºF and spray a baking sheet with cooking spray.

Then, place the tomatoes, red onion, vinegar, and ¼ teaspoon salt in a bowl. Mix and set aside. 

Next, lightly dust a flat counter top with flour and lay out the puff pastry sheet onto the flour. 

Dust a rolling pin with flour and roll out the puff pastry to a 9x13-inch thin crust. It does not have to be exact, just close!

Transfer the puff pastry to the baking sheet and carefully fold the edges of the puff pastry in 1-inch, creating a crust for the tart. 

Then, take a knife and score along the folded edge of the puff pastry, trying not to cut all the way through to the baking sheet. 

Take a fork and poke small holes in the center of the tart so that the middle doesn’t puff during the bake time. 

Lastly, brush the puff pastry with an egg wash. 

Place the puff pastry in the oven and bake for 12-15 minutes. 

While the crust is baking mix the cream cheese, lemon zest, lemon juice, and fresh thyme into a bowl until creamed and combined. 

Remove the crust from the oven and carefully spread the cream cheese mixture in the center of the tart. 

Bake for an additional 8-10 minutes. 

Remove from the oven and let cool for 5 minutes. 

Pour the tomatoes and onion into a sieve and drain excess liquid from the vegetables. 

Evenly spread the tomatoes and onion out over the cream cheese. 

Top with fresh thyme and optional balsamic glaze.