• Line a 9x9-inch square pan with parchment paper, making sure there’s enough overhang on all sides so you can lift the bars out easily later.

For the crust:

• In a microwave-safe bowl, add the butter, brown sugar, salt, cinnamon, and nutmeg.
• Microwave in 30-second bursts, stirring after each one, until the mixture is bubbling and the sugar is mostly dissolved, about 2 to 2 ½ minutes.
• Stir in the almond extract, Oreo crumbs, and ground pistachios until everything is evenly moistened.
• Pour the crust mixture into your prepared pan and press it down firmly and evenly, going slightly up the sides.
• Pop it into the freezer to chill for 20 to 30 minutes until firm.

For the filling:

• In a large bowl, beat together the cream cheese, confectioners’ sugar, and lemon juice until smooth and creamy, about 2 minutes.
• Add the vanilla, almond extract, and salt, and beat again until combined. Mix in the pistachio cream and tahini until smooth.
• Finally, pour in the cold heavy cream and beat until the filling thickens and holds its shape, about 5 minutes.
• Take the crust out of the freezer and pour the filling over it.
• Spread it evenly with a spatula and tap the pan on the counter a few times to get rid of any air bubbles.
• Return the pan to the freezer and let it chill until the filling feels mostly set, at least 3 hours.

For the ganache:

• Place the chocolate chips in a bowl. In a microwave-safe measuring cup, heat the ¾ cup of cream and corn syrup until it just starts to bubble, about 2 ½ minutes.
• Pour the hot cream over the chocolate chips and let it sit for about 3 minutes, then gently stir until the ganache is smooth and glossy.
• Take the bars out of the freezer and pour the ganache on top, spreading it into an even layer.
• Sprinkle 2 tablespoons of chopped pistachios over the top.
• Put the bars back in the freezer for about 15 minutes so the ganache can set. (It will stay a little soft and creamy.)

To serve:

• Remove the bars from the freezer and lift them out of the pan using the parchment paper overhang.
• Place on a cutting board and peel off the parchment. Run a sharp knife under hot water, wipe it dry, and slice the bars, cleaning the knife between each cut.
• Keep any extras stored in the freezer, and let them sit at room temperature for 20 to 30 minutes before serving for the perfect creamy texture.