Line a 9x13-inch baking pan with parchment paper, allowing some overhang for easy removal later. Lightly coat the parchment and sides with cooking spray.

In a food processor, pulse 1 cup of walnut pieces until they resemble coarse crumbs. Add 1.5 cups of all-purpose flour, 0.5 cup of powdered sugar, 1 teaspoon of ground cinnamon, and a pinch of salt. Process until finely ground.

Add 0.5 cup of unsalted butter to the food processor. Pulse until the mixture forms moist clumps, then transfer to the prepared pan and press down firmly.

Refrigerate the pressed crust for 30 minutes. Preheat your oven to 350°F (175°C). Bake the crust for 20-25 minutes until lightly golden.

In a saucepan, combine 3 cups of cranberries with 0.5 cup of water over medium heat. Stir occasionally until the cranberries burst, about 10 minutes. Strain the mixture to collect the puree.

In a medium bowl, mix the cranberry puree with 1.25 cups of granulated sugar, 3 large eggs, 2 large egg yolks, lemon juice, and a pinch of salt. Whisk until well combined.

Pour the curd mixture into a saucepan over low to medium heat, stirring continuously for about 5-11 minutes until it thickens and reaches 150°F (65°C).

Remove the curd from heat and stir in 0.5 cup of unsalted butter until melted. Pour the curd over the baked crust and smooth it out evenly. Return to the oven and bake for an additional 10-15 minutes until set.

Allow the bars to cool on a wire rack for about an hour. Transfer to the refrigerator and chill until thoroughly chilled, preferably for a couple of hours. Dust with powdered sugar before serving and cut into 24 bars.