Place egg yolks and whipping cream in a medium-sized mixing bowl.

Using the back of a knife, scrape the caviar from the vanilla bean. Add the caviar to the egg yolks and cream. Whip to combine and set aside.

In a large food processor, fitted with a dough blade, place flour, sugar, and salt. Blitz briefly to combine.

Set the food processor to low and add the butter to the flour mixture piece by piece. Blitz until the mixture resembles a coarse meal.

With the food processor still running, stream in the yolk/cream mixture. Blitz until a dough forms.

Turn the dough onto a well-floured surface. Divide the dough into two and form each half into discs. Wrap and freeze 1 half for later use. Place the other half in the fridge for 2 hours.

When thoroughly chilled, remove the dough from the fridge and let sit at room temperature for 15-20 minutes.

Place the dough on a well-floured surface, and roll it out to 1/8-inch thickness.

Cut the dough into six squares and fit them into 3-inch tart pans. Trim the edges and chill for 1 hour.

While the dough is chilling, preheat the oven to 400F.

Pierce the tart shells all over with a fork. Line the shells with a piece of parchment and place a handful of dried beans in the center.

Bake the shells for 15-20 minutes or until golden. Let cool completely before filling.

Pour half and half in a small saucepan. Add the sugar, salt, cardamom pods, cinnamon stick and saffron, and place the pot over medium-low heat.

Cook until the sugar dissolves and the milk is steaming but not boiling. If it starts to boil, remove the milk from the heat immediately.

While the milk is heating up, whisk egg yolks and cornstarch together in a medium-sized bowl. Whisk until the mixture is thick and pale yellow.

Strain the hot milk and discard the solids. Return the milk to the saucepan.

Add a ladle-full of the hot milk to the egg yolk mixture and whisk immediately to temper the eggs.

Pour the egg mixture into the milk mixture and return the saucepan to medium heat. Cook until the mixture reaches a pudding-like consistency.

Remove the pastry cream from the heat and immediately add the butter. Stir until the butter melts and is fully integrated into the pastry cream.

Transfer the cream to a bowl, cover and chill for two hours.

Remove the tart shells from their pans and set aside.

Spoon pastry cream into the tart shells and smooth out the surface using a small palette knife.

Arrange blackberries and blueberries on top of the pastry cream.

Transfer the remaining pastry cream to a pastry bag fitted with a Wilton #10 round tip. Pipe pastry cream into any spaces visible on the surface of the tart.

Garnish with fresh mint leaves and chill until ready to serve.