Drain ricotta cheese overnight in a fine-mesh sieve lined with cheesecloth; this ensures a thick filling.
In a bowl, combine drained ricotta, powdered sugar, vanilla extract, and cinnamon; mix until smooth. Fold in mini chocolate chips and refrigerate for at least 30 minutes.
Preheat oven to 375°F (190°C). Roll out pie crusts and cut into squares. Brush each square with egg wash and sprinkle with sugar. Bake for 10-15 minutes until golden brown; cool completely.
Assemble by piping ricotta filling onto one pastry square and topping it with another square. Repeat for desired layers.
Garnish with powdered sugar, chopped pistachios, or cherries before serving.