Preheat oven to 350 degrees.
Mix together the hummus, Greek yogurt and ranch seasoning in a medium bowl. Set aside.
Gently roll out one pastry sheet on parchment paper (to remove the fold seams) and roll into a square.
Transfer the parchment paper and pastry to a baking sheet.
Place approximately 1 cup of the hummus mixture in the center of the pastry and use an offset spatula or knife to spread the hummus evenly over the pastry, making sure to leave a 1½" border around all sides.
Place the sliced tomato and zucchini over the hummus, alternating as you go.
Season the tomatoes and zucchini a drizzle of olive oil, salt and pepper to taste, and sprinkle evenly with the Parmesan cheese.
Wet the dough of the pastry border with a bit of water on all four sides. Set aside.
Gently roll out the second pastry sheet (on parchment paper) to form a square.
Use a pizza wheel to cut the rolled pastry into twelve even strips.
Place 6 strips of the pastry evenly spaced over the tomato and zucchini slices.
Make a basket weave pattern with the remaining pastry strips by alternating every other strip of the first six strips down, and by folding back and replacing the strips in place until a lattice pattern forms. (see photos in post)
Use the pizza wheel to trim the excess pastry and make the edges even.
In a small bowl use a fork to mix the egg and 1 tablespoon of water.
Use a pastry brush to brush the egg wash over the lattice dough.
Bake in a preheated 350 degree oven for 50-60 minutes or until the dough is puffed and golden.
Allow the tart to cool completely and then use a couple of large spatulas or a cake lifter to remove the tart from the parchment paper and place it on a serving platter.
Serve warm or at room temperature.
Enjoy!