First, make the crust. Preheat oven to 350F and prepare a 10" tart pan.

Melt the butter in a microwave-safe bowl.

In a large bowl, combine the flour, sugar, powdered sugar. and salt. Add in the melted butter, and mix until well-combined.

Press the dough into your prepared tart shell, making sure to press tightly up the sides.

Place in fridge for 15 minutes to chill.

Line the tart shell with a piece of foil, and fill with pie weights or dry beans. Bake crust for 30 minutes.

Remove foil and weights, brush with the egg white, and bake for 8 more minutes, until lightly golden but not brown.

Set aside to cool, and lower oven to 325F while you prepare the filling.

Heat the cream and milk in a medium nonstick saucepan over medium heat, until bubbles start to form around the edges.

Remove from heat, and add the chocolate, stirring until melted and smooth.

Add sugar and salt, whisking until well-incorporated.

In a separate small bowl, beat the two eggs well, then add a little at a time, whisking vigorously until incorporated.

Pour the filling into the tart crust, filling about ¼-1/8 inch below the rim.

Bake the tart for 15-20 minutes, until the filling is set and glossy, but not cracked or bubbling - that means it’s overcooked!

Let cool to room temperature, and for best results, refrigerate for 2-3 hours before serving so the filling can firm up.