Cream together the butter, sugar, and salt until smooth. Add in the egg and mix until incorporated, then scrape down the sides. Add the flour and mix on low until just incorporated.

Wrap the dough in plastic wrap and flatten into a 1 inch thick disc. Place in the fridge for about two hours.

Remove the dough from the fridge and plastic wrap and allow it to sit at room temperature for 15 minutes. Lightly flour your work surface and roll out the dough until it’s ⅛-¼" thick.

Transfer the dough to the pan and press it into the bottom, corners, and sides of the tart pan. Roll the rolling pin over the top to remove the excess dough.

Transfer to the freezer for 15 minutes, and preheat the oven to 325℉. Dock the bottom of the tart with a fork multiple times and line the shell with parchment paper and fill completely with pie weights.

Bake for 10 minutes. Carefully remove the weights and parchment, and continue to bake for another 10-15 minutes until lightly golden. Remove the pan to a wire rack to cool completely.

In a small saucepan over medium heat, cook down the blueberries, mashing with the back of a wooden spoon, until juices develop and the liquid starts to bubble.

Using a fine mesh strainer, strain the blueberry mixture into a bowl. Measure out ¼ cup of the strained blueberry liquid and set aside.

Add the chopped white chocolate to a heatproof bowl and set aside. In a saucepan over medium high heat, bring the heavy cream to a simmer.

Once simmering, pour the hot cream over the chocolate, add the blueberry liquid and vanilla extract, and allow it to stand for a minute. Stir until the mixture is smooth and glossy.

Pour the blueberry white chocolate ganache into the cooled tart shell and place in the fridge for two hours to set.

Before serving, allow the tart to come to room temperature for 30 minutes.

Fill a saucepan with about 1 inch of water and turn to high heat. Add a heat proof bowl over top.

To the bowl, add the egg whites, sugar, and salt and whisk to combine. Continue whisking until warm and the sugar has dissolved.

Once the mixture is ready, add it to the bowl of a stand mixer fitted with the whisk attachment and whip on medium speed for about a minute. Then whip until stiff peaks form.

Once the meringue hits stiff peaks, add the vanilla and mix once more to combine.

Pipe on any decoration of your choosing.