1. To make the base, use a food processor to process flour, sugar, cocoa and salt until combined. Add butter and process until the mixture resembles breadcrumbs. Add egg yolks and blend until combined and forming clumps. Knead the mixture on a lightly floured surface until it comes together and is smooth, wrap in clingfilm and refrigerate for 30 minutes to an hour. 

2. Preheat oven to 180C, roll out pastry on a lightly floured surface and then press into the base and sides of a 24cm loose bottomed flan tin. Trim the edges and refrigerate for 30 minutes to an hour. 

Note: For a tidier finish combine a little cocoa with the flour used on the surface to roll out dough, to avoid white patches on the outside of the tart pastry. 

3. Prick pastry all over with a fork, then line with baking paper and add pastry weights.

Note: To make the baking paper easier to line the tart pastry, scrunch it in to a ball first and then spread out again.

4. Bake for 15 minutes, then remove paper and weights and continue to bake for a further 5 minutes until crisp. 

5. Reduce oven temperature to 140C and make the filling. Place chocolate orange dotties in a bowl. Heat the cream and milk over medium heat until it just reaches simmering point, remove from heat and pour over chocolate orange dotties. Leave to sit for couple of minutes and then stir to combine. Add eggs and stir gently until combined. Strain mixture through a sieve into a large jug. Pour into tart case and bake for 30 minutes or until filling has just set and has a slight jiggle in the centre. Set aside to cool completely.

6. To make the ganache topping, place dark chocolate dotties in a bowl, heat cream until it just reaches simmering point, do not let it boil. Remove from heat and pour over the chocolate dotties. Leave to sit for a few minutes and then stir to combine. Gently pour over tart filling evenly. Refrigerate for about one hour, until chocolate is set. 

7. To decorate, sprinkle some biscuit crumb in an arch close to the edge on one side. Top with rounds of fresh and dried orange, blueberries and gingerbread bites.

Bring tart to room temperature to serve. Serve with vanilla ice cream.