Preheat your oven to 350°F (175°C).

In a food processor, combine gingersnaps, walnuts, and brown sugar until finely crumbed. Drizzle in melted butter and pulse until it resembles wet sand.

Press the crumb mixture into a 9-inch pie plate and bake for 10-15 minutes until edges are slightly browned. Allow to cool completely.

In a saucepan, cook cranberries with 2 cups of sugar and some water over medium heat until cranberries burst and mixture thickens, about 15 minutes. Puree until smooth.

Whisk together pureed cranberries, eggs, egg yolks, lemon juice, and remaining sugar in a saucepan. Cook over medium heat, stirring constantly for about 10 minutes until thickened.

Strain the mixture through a sieve into a bowl to remove lumps. Return to low heat, whisk in room temperature butter until smooth.

Pour the filling into the cooled crust and chill in the refrigerator for about 2 hours to set.

Garnish with sugared cranberries and fresh herbs before serving. Serve chilled or let sit at room temperature.