Preheat the oven to 350 °F and get out a 9" tart pan with a removable bottom.

In a large mixing bowl, stir together the sugar, flour, cocoa powder and salt. Stir in the melted butter until well combined and a dough forms.

Press up the sides and over the bottom of the tart pan.

Bake for 10 minutes. It'll have started to bubble slightly and will still be quite soft. Let cool for at least 10 minutes before filling.

After 10 minutes of cooling, the sides of the crust will be firm and the center will still be quite soft.

While the crust is baking and cooling, prepare the filling.

In a medium saucepan over medium-low heat, mix together the chocolate and whipping cream and stir frequently until the chocolate is melted. Remove from the heat. It shouldn't be that warm but if it is, let it cool about 5-10 minutes so that the eggs don't scramble when added.

Stir in the peppermint and vanilla extracts followed by the beaten eggs.

Place the tart pan on a baking sheet, which will make removing the tart from the oven easier.

Pour the filling over the partially cooled crust and bake for 22-27 minutes or until the center is set. When you tap the pan, there shouldn't be any ripples, but it won't be totally firm.

Let cool for about 1 hour and then chill for another 2 hours.

Dust with cocoa powder and top with mint leaves prior to serving, if desired.