Preheat your oven to 350°F (175°C). Blitz the ground ginger-nut biscuits until they resemble fine crumbs.

Melt the unsalted butter and pour it over the biscuit crumbs, mixing until wet sand forms.

Press the mixture into a 23 cm tart tin and bake for 10 minutes until lightly golden. Allow to cool.

Once cooled, pour the caramel sauce over the base, spreading gently. Let sit for about 10 minutes.

In a bowl, combine dark chocolate, milk chocolate, unsalted butter, heavy cream, and ground ginger. Melt in the microwave, stirring until smooth.

Pour the ganache over the caramel layer and smooth it with a spatula. Chill in the refrigerator for at least 4 hours.

Melt remaining dark chocolate and drizzle over the tart. Sprinkle with crushed gingerbread crumbs or sprinkles.

Slice using a hot knife and serve with whipped cream or a scoop of vanilla ice cream.