Step 1: Prepare the Springform Pan.

Preheat the oven to 350°F (175°C).

Wrap the bottom and sides of a 9-inch round springform pan tightly with aluminum foil. This creates a waterproof seal.

Lightly grease the inside of the pan with nonstick cooking spray. Set the pan aside.

Step 2: Make the Crust.

Place the graham crackers, pistachios, brown sugar, and salt in the bowl of a food processor.

Process until finely ground, about 30 seconds. The mixture should resemble coarse sand.

Drizzle the melted butter over the top of the graham cracker mixture.

Process until the mixture is evenly moistened. It should hold together when pressed.

Transfer the crust mixture to the prepared springform pan.

Using a measuring cup or your fingers, press the crust into the bottom of the pan.

Press firmly to pack and make an evenly thick crust.

Bake the crust until it is lightly browned and smells toasty, 12 to 14 minutes.

Cool the crust completely, about 30 minutes. This is important for preventing a soggy crust.

Step 3: Make the Filling.

Place the ricotta and softened cream cheese in the bowl of a food processor.

Puree until very smooth, about 30 seconds. Scrape down the sides of the bowl as needed.

Add the sugar, flour, eggs, orange zest, vanilla extract, and salt.

Process until smooth, about 30 seconds. Stop the food processor as needed to scrape the sides.

Step 4: Assemble and Bake the Cheesecake.

Pour the filling into the cooled crust. Spread it evenly.

Place the springform pan in a roasting pan.

Pour boiling water into the roasting pan to come halfway up the sides of the springform pan. This creates a water bath.

Bake at 350°F (175°C) until the cheesecake is mostly set with a slight jiggle in the center, 1 hour 20 minutes to 1 hour 30 minutes.

Step 5: Cool and Chill the Cheesecake.

Carefully remove the cheesecake from the water bath to a wire rack.

Let it cool to room temperature, about 2 hours.

Remove the aluminum foil from the pan.

Refrigerate the cheesecake until cold and set, at least 6 hours, or preferably overnight.

Step 6: Release and Garnish the Cheesecake.

Run a paring knife around the sides of the pan to loosen the cheesecake.

Remove the sides of the springform pan.

Garnish the cheesecake with chocolate shavings and chopped pistachios, if desired.

Slice and serve chilled.