For the pitas:
For the dip:
Make the pitas:
Preheat the oven to 350°F. Brush one side of each pita round with pesto. Stack the pitas and cut the stack into 8 pieces to yield 32 triangles. Arrange the triangles on baking sheets and bake until golden, 10-11 minutes.
Make the dip:
Preheat the oven to 350°F. Pulse the spinach and artichokes in a food processor until chunky-smooth. Add the yogurt, pesto, 2 cups of the mozzarella, the Parmigiano Reggiano cheese, oregano, salt, and pepper. Grease an 8 x 10-inch oven-safe dish and transfer the mixture to the dish. Top with the remaining 1/2 cup mozzarella cheese. Bake until golden and bubbly, 35-40 minutes. Serve with the pita chips. (Dip can be made ahead, then baked before serving; pitas can be made up to 2 days in advance and stored in an airtight container.)