Authentic Turkish Delight (Lokum)

In a medium saucepan, combine 4 cups granulated sugar, 1 cup water, and lemon juice. Stir over medium heat until sugar dissolves, then bring to a boil without stirring. Use a candy thermometer to cook until it reaches 240°F (soft-ball stage), about 10-15 minutes.

In a separate large saucepan, whisk together 3/4 cup cornstarch, cream of tartar, and remaining 1/2 cup water until smooth to form a slurry.

Slowly pour the hot sugar syrup into the cornstarch slurry while whisking constantly. Cook over medium heat, stirring continuously with a heatproof spatula, until the mixture thickens and becomes glossy, pulling away from the sides of the pan, about 10-15 minutes. It should reach around 250°F.

Remove from heat and stir in rosewater, pink food coloring (if using), and chopped nuts. Pour immediately into the prepared pan, spreading evenly with an oiled spatula.

Let cool at room temperature for 1 hour, then cover loosely and refrigerate for at least 4 hours or overnight until fully set and firm.

Unmold the delight onto a cutting board dusted with powdered sugar and cornstarch mixture. Cut into 1-inch cubes using an oiled knife.

Roll each piece in the powdered sugar-cornstarch mixture to coat generously. Store in an airtight container between sheets of parchment paper for up to 2 weeks.