Drain the ricotta: Place ricotta cheese in a fine mesh strainer lined with cheesecloth. Set over a bowl, cover, and refrigerate for 24 hours to remove excess moisture. This step ensures a creamy yet stable filling.
Make the filling: In a large mixing bowl, combine the drained ricotta, pumpkin puree, powdered sugar, and pumpkin pie spice. Stir gently with a spatula until smooth and fully combined. Avoid overmixing to keep the texture light.
Pipe into shells: Transfer the filling into a piping bag fitted with a large round or star tip. Pipe the mixture into both ends of each cannoli shell, filling completely.
Serve: For best results, fill cannoli shells 2–4 hours before serving to prevent softening. Dust lightly with extra powdered sugar if desired.
Notes
Allow the ricotta to drain properly to achieve the right texture for the filling.
Avoid using pumpkin pie filling as it contains added sugars and spices.
Fill the cannoli shells just before serving for optimal crispiness.