In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter. Mix until the mixture resembles wet sand. Line a 9x9-inch baking pan with parchment paper, leaving an overhang for easy removal. Press the crumb mixture firmly into the bottom of the prepared pan, forming a slightly raised edge. Bake at 350°F for about 10 minutes until golden and fragrant, then let it cool slightly while preparing the filling.

Using an electric mixer, beat the room-temperature cream cheese and granulated sugar in a large bowl until smooth and creamy, about 2 minutes. Gradually add the eggs, one at a time, ensuring each is fully incorporated before adding the next. Mix in the vanilla extract and then gently fold in the ricotta cheese and mini chocolate chips, creating a luscious, thick batter.

Pour the creamy filling over the pre-baked crust in the pan, smoothing the top with a spatula for an even layer. Bake in the preheated oven at 325°F for 40-45 minutes.

Once baked, turn off the oven and crack the door open, allowing the bars to cool gradually for 30 minutes. After the initial cooling, transfer the pan to room temperature to finish cooling for about 1 hour before refrigerating. Chill in the fridge for at least 4 hours or overnight to fully set.

Before serving, remove the bars from the refrigerator and dust the top with powdered sugar. Use the parchment overhang to lift the bars out of the pan and cut them into squares.