To make the crust, combine the flour and salt in a medium bowl. Add the butter cubes, and using a pastry cutter or a fork, cut the butter into the flour until the pieces are the size of a pea or smaller.  Slowly add the water, 1 tablespoon at a time, adding just enough to bring the dough together.  (You may need a little less water or a little more water depending on external circumstances.)  Form into a disc and wrap tightly in saran wrap.  Refrigerate for 1 hour.

Dice the bacon, then cook in a medium skillet over medium heat until browned and crispy.  Transfer to a paper towel lined plate.

In a bowl, combine the ricotta and the pesto. 

Preheat the oven to 400ºF.

Remove the dough from the refrigerator and roll into a 12-inch circle on a sheet of parchment paper.  Spread the ricotta mixture over the dough, leaving a 1-inch border. Sprinkle the bacon over the cheese, reserving some for topping, if desired.  Arrange the zucchini over the top, then fold the edges of the dough over, crimping as necessary.  Drizzle the olive oil over the top of the zucchini.  Transfer the tart, keeping it on the parchment paper, to a baking sheet.

In a small bowl, beat the egg with a splash of water, then brush the mixture over the edges of the crust.

Bake in the tart in the oven until the crust is browned, about 30 minutes.  Let sit for 5 minutes before serving. Top with basil before serving.