Preheat your oven to 350°F (175°C).

In a food processor, combine gingersnap cookie crumbs, melted unsalted butter, light brown sugar, and a pinch of kosher salt. Pulse until the mixture resembles wet sand. Firmly press into a 9-inch pie dish, creating an even layer. Bake for 12-13 minutes, until fragrant and crispy. Allow to cool completely.

In a medium saucepan, add fresh cranberries, 1 cup of granulated sugar, and ¼ cup of water. Bring to a rolling boil, then reduce to a simmer. Cook for about 15-20 minutes until cranberries burst and sauce thickens. Remove from heat and cool slightly before pureeing until smooth.

In a large mixing bowl, incorporate cranberry puree with three large eggs, two egg yolks, Meyer lemon zest, Meyer lemon juice, and remaining granulated sugar. Whisk until fully combined.

Transfer filling mixture to a heatproof bowl set over simmering water. Stir continuously for 15-20 minutes until thickened, reaching 165°F (74°C). Strain through a fine-mesh sieve into a clean bowl.

Gradually add softened room-temperature butter to the filling mixture, stirring vigorously to ensure a smooth consistency.

Pour the filling into the cooled gingersnap crust and smooth the top. Cover loosely with plastic wrap and refrigerate for at least 8 hours, preferably overnight.

When ready to serve, top with optional sugared cranberries and a generous dollop of fresh whipped cream.