Drain ricotta in a strainer over a bowl in the refrigerator overnight. Discard the liquid that drains out.
Using a handheld or stand mixer, place the cream and a half cup of powdered sugar into a bowl.
Beat on medium speed until cream begins to firm up and look like whipped cream. Do not overmix.
Transfer to another bowl and wash out the mixing bowl.
Place the strained ricotta and the other half cup of powdered sugar into the cleaned mixing bowl.
Beat for 1 minute on medium speed.
Add the mascarpone and vanilla extract and beat on low until combined, about 30 seconds. Do not overmix.
Add whipped cream and beat on low until combined, about 20 seconds.
Fold in the chocolate chips and lemon zest with a rubber spatula or spoon.
Divide the filling between the 12 mini pie crusts.
Serve immediately or refrigerate until ready to serve.
Sprinkle with chocolate chips before serving. Enjoy!