Rinse fresh cranberries under cold water, then combine in a saucepan with ½ cup water and ½ cup granulated sugar. Cook over medium heat until cranberries soften, about 10 minutes. Allow to cool slightly.

Preheat your oven to 325°F (163°C). Line a 9-inch square baking dish with parchment paper and lightly grease it.

In a mixing bowl, combine melted butter, granulated sugar, vanilla extract, salt, and flour until crumbly. Press into prepared pan and bake for 16-18 minutes until golden brown. Let cool.

In a large bowl, whisk together flour and sugar. Add eggs and lemon juice, mixing until smooth.

Spread the cooled cranberry mixture over the shortbread crust. Chill for 45 minutes.

Pour the lemon custard mixture over the chilled cranberry layer. Bake in the oven at 350°F (177°C) for 43-45 minutes until set.

Allow the bars to cool at room temperature for 30 minutes, then refrigerate for at least 1-2 hours.

Lift the bars out using parchment overhang. Dust with powdered sugar and slice into squares.