In a large mixing bowl, combine gluten-free flour, ground ginger, and sugar. Cut in cold unsalted butter until the mixture resembles small peas. Gradually add ice water and mix until dough forms. Shape into a disc, wrap in plastic, and chill for at least 30 minutes.

Preheat your oven to 375°F (190°C). Roll out the chilled ginger pastry crust until 1/8-inch thick, fit into a 9-inch pie pan, and trim excess. Line with parchment paper and fill with weights. Bake for 15-20 minutes until edges are golden. Remove weights and cool.

In a medium saucepan, combine fresh cranberries, granulated sugar, and pure cranberry juice. Cook over medium heat, stirring until cranberries burst, about 10 minutes. Blend until smooth and strain to yield about 2 cups of puree.

In a large mixing bowl, whisk together the large eggs. Gradually add warm cranberry puree while whisking to prevent scrambling. Stir in heavy cream until smooth.

Pour custard filling into the cooled crust. Bake at 375°F (190°C) for 25-30 minutes. The edges should be set, and the center remains slightly wobbly.

After baking, cool the pie at room temperature for at least 1 hour, then refrigerate for a minimum of 6 hours or overnight before serving.