Preheat oven to 400 degrees F. Thaw your puff pastry according to package instructions.

While pastry is thawing, slice tomatoes crosswise into 1/4-inch slices. Place on paper-towel lined plate and sprinkle with kosher salt. Let sit at room temperature while you prep the rest of the tart.

In small bowl, whisk egg and milk until smooth.

In medium bowl, use a fork to mash together ricotta, Parmesan and lemon zest until well combined.

Unwrap puff pastry and place on a piece of parchment paper on work surface. Use rolling pin to lightly roll out to 10 by 12-inch rectangle. Transfer parchment with pastry to rimmed baking pan. Use sharp paring knife to score a 1-inch border around the outside of the pastry (take care to not cut all the way through the pastry).

Use an offset spatula or small knife to spread ricotta mixture evenly inside the scored border. It’s honestly a little tricky to spread, since the mixture can be crumbly. Keep working at it, and it will eventually spread!

Arrange tomatoes over ricotta, overlapping slightly if needed.

Brush border of tart with egg mixture. Transfer to oven and bake 24 to 26 minutes or until edges are puffed and dark golden brown. Remove from oven and let cool on pan for 5 minutes before serving.

To serve, drizzle with olive oil and sprinkle with basil, sea salt and black pepper. Cut into 8 pieces and serve right away.