DRAIN RICOTTA: Add 16 ounces whole milk ricotta cheese to a fine-mesh sieve set over a bowl. Let drain for at least 30 minutes, until most of the liquid releases. Discard liquid.
CHILL TOOLS: While the ricotta drains, place a metal mixing bowl and electric mixer beaters in the freezer to chill.
WHIP CREAM: Add ⅓ cup heavy cream to the chilled bowl. Using an electric mixer, beat on high speed for 2 to 3 minutes, until stiff peaks form. Add ½ cup powdered sugar and beat just until combined and smooth.
MIX BASE: In a separate large bowl, add the drained ricotta, 1 teaspoon vanilla extract, lemon zest from 1 lemon, and ¼ teaspoon ground cinnamon. Stir until smooth and creamy.
FOLD: Gently fold the whipped cream into the ricotta mixture using a silicone spatula until fully incorporated and fluffy. Cover and refrigerate for at least 30 minutes.
FILL CANNOLI: Transfer the filling to a piping bag fitted with a tip. Pipe filling into cannoli shells. Sprinkle ½ cup mini chocolate chips onto each end and dust with powdered sugar before serving.
Notes
Make-Ahead: The filling can be made up to 24 hours in advance. Store covered in the refrigerator.Storage: Store leftover filling in an airtight container in the refrigerator for up to 3 days.Freezing: Freezing is not recommended. The texture changes once thawed.Ingredient Note: Whole milk ricotta gives the best creamy texture. If your ricotta seems wet, extend draining time to 45 minutes.Pro Tip: Always use a metal bowl for whipping cream. Plastic warms too quickly and glass can crack from temperature shock.