Preheat your oven to 350°F (175°C). Line a 9×9-inch baking pan with parchment paper, leaving overhang on two opposite sides to create handles. Lightly grease the pan under the parchment if desired to help it stay in place.
parchment paper, nonstick spray or butter
In a medium mixing bowl, whisk together the flour, granulated sugar, cinnamon, and salt for the crust. Pour in the melted, slightly cooled butter and vanilla extract. Stir until the mixture resembles damp sand and starts to clump; it should be crumbly but hold together when pressed.
1 1/2 cups all-purpose flour, 1/2 cup granulated sugar, 1/2 cup unsalted butter, 1/4 teaspoon kosher salt, 1 teaspoon vanilla extract, 1/2 teaspoon ground cinnamon
Transfer the crust mixture to the prepared pan and press it firmly and evenly into the bottom using your fingertips or the bottom of a measuring cup. Bake for 10–12 minutes, just until the crust looks set and slightly puffed but not browned. While the crust bakes, prepare the filling.
In a large bowl, beat the softened cream cheese with a hand mixer on medium speed until smooth and fluffy, 1–2 minutes. Add the ricotta and beat again until very smooth and well combined, scraping down the sides of the bowl as needed.
2 cups whole milk ricotta cheese, 4 oz cream cheese
Add the granulated sugar, powdered sugar, salt, vanilla extract, almond extract (if using), and orange zest to the ricotta mixture. Beat on medium speed until creamy and slightly thickened, about 1–2 minutes.
1/2 cup granulated sugar, 1/4 cup powdered sugar, 1/4 teaspoon kosher salt, 1 teaspoon vanilla extract, 1/2 teaspoon almond extract, 1 tablespoon orange zest
Add the eggs one at a time, mixing on low speed just until each egg is incorporated. Do not overmix. Gently fold in the mini chocolate chips with a spatula until evenly distributed.
2 large eggs, 3/4 cup mini chocolate chips
When the crust comes out of the oven, let it cool for about 5 minutes. Pour the ricotta filling evenly over the warm crust and spread it into the corners. If using pistachios, sprinkle them evenly over the top.
1/4 cup pistachios
Return the pan to the oven and bake at 350°F (175°C) for 30–35 minutes, until the edges are set, the center is mostly set with a slight wobble, and a toothpick inserted near the center comes out mostly clean with a few moist crumbs. If the top begins to brown too quickly, tent loosely with foil for the last 5–10 minutes.
Remove the pan from the oven and place it on a wire rack. Cool completely to room temperature, then cover and chill in the refrigerator for at least 3 hours, preferably overnight, until the filling is fully set.
Use the parchment overhang to lift the chilled slab out of the pan onto a cutting board. For the cleanest cuts, run a sharp knife under hot water, wipe dry, and slice into 16–20 bars, wiping the knife between cuts. Serve chilled or slightly cool.