In a food processor, combine the flour and sugar with a few quick pulses. Add in the butter cubes and pulse until the dough resembles small peas. This will take about 10-12 seconds. Then keep the food processor on while you add the egg yolks and the ice water. Keep blending until the dough forms a ball.

Take out the dough and divide it into 2 balls and flatten them into discs. Wrap each disc with plastic wrap and chill in the refrigerator for one hour or more.

Working with one disc at at time, roll out the dough on a lightly floured surface. Roll until the dough is 1/8" thick and then cut out circles a bit larger than the tart tins you're using. Press the dough rounds into the tart tins. Then chill the dough in the tart tins for another hour.

Preheat the oven to 375 ℉.

Take the tarts out of the fridge and place them on a larger baking sheet. Bake for 17-20 minutes. Rotate the pan halfway through the cooking time. Then take them out of the oven and cool for 10 minutes. Gently take the crusts out of the pans and put them on wire racks to cool.

Make a double boiler by placing a small glass box over a pan of simmering water. Place the chocolate in the bowl and stir until it is melted. Remove the bowl from the heat and allow it to cool for 10 minutes.

While you're waiting, cut the vanilla bean in half with a sharp knife and scrape the seeds out of each half. In another bowl, whisk together the seeds with the mascarpone cheese. Then slowly whisk the melted chocolate into the cheese. Set aside.

With a stand mixer, beat the whipping cream into soft peaks and then gently fold the whipped cream into the mascarpone/vanilla batter.

Divide the vanilla cream evenly between all the tarts and spoon the cream into each tart shell. Top with the blackberries and sprinkle with confectioner's sugar. Serve immediately.