Add flour, cocoa powder, sugar and salt in a mixing bowl and mix thoroughly with a whisk. Transfer flour mixture to a food processor fitted with the dough blade.

Add cubed cold butter to the flour mixture. Pulse the food processor several times until butter is about pea and bean size. Variations in size are okay.

Turn the food processor to “on” position and drizzle cold water over the dough mixture through the water hole, as soon as the dough starts to pull together turn the food processor off. You may need to stop the food processor in between and get a spatula to mix up the flour at the bottom.

Turn the dough out on the counter or cutting board lined with a piece of plastic wrap, and shape into a disk. Wrap well and rest in the refrigerator for at least an hour.

Take the disk of pie dough out of the fridge and roll into a circle about 2” larger than your pie dish. Use extra flour to keep the dough from sticking to the counter and roller.

Carefully place the dough over the pie dish, lightly press the dough into the bottom and side of the pie dish, let the excess dough hang over the side. Trim the excess dough leaving just enough to fold under and create a fluted edge.

Cover the pie dish with plastic wrap and keep refrigerated, or freeze (preferred), for 15 - 30 minutes.

Preheat the oven to 425°F.

Remove pie crust from the freezer and use a fork to poke steam vents on the bottom of the pie dough and on the sides.

Place a large piece of parchment paper over the frozen pie dough, place pie weights on top or pour dry beans on top to fill the whole pie crust. Make sure the parchment is large enough to cover the edges of the crust entirely.

Place the pie dish on a large baking sheet. Bake pie crust for 25 minutes with pie weights or beans, then carefully remove the pie weights and peel off the parchment paper. Use strips of foil to make an edge shield, and bake for another 7 - 10 minutes until the crust is fully baked, and the bottom surface is dry.

Remove the pie crust from the oven and let it cool completely on a wire rack.

Melt the chocolate in a double boiler or in a heatproof bowl set over a steaming pot of water. Set aside to cool.

Heat the eggs and ½ cup of granulated sugar in a double boiler or in a small saucepan set over low heat until the mixture reaches 160°F, whisking constantly so the eggs don’t cook. This will take about 5 - 7 minutes. At this point the egg mixture should be foamy but still a liquid.

Take it off the heat and add it to the slightly cool melted chocolate and whisk until thoroughly incorporated. Set aside to cool. Tip: to ensure a smoother texture, you could also strain the egg mixture through a fine mesh sieve into the melted chocolate.

Add ¾ cup of heavy whipping cream and 1 tablespoon of granulated sugar to a stand mixer bowl, beat on medium speed. Stream in ½ teaspoon of vanilla and continue beating until stiff peaks. Scoop it into a small bowl and refrigerate until needed.

In the same stand mixer bowl, add the softened butter and the remaining granulated sugar, 1 teaspoon of vanilla extract, and beat until light and fluffy, about 2 - 3 minutes. Add the cooled chocolate and egg mixture, beat another 2 - 3 minutes until completely smooth. Scrape the side and bottom of the bowl as necessary to ensure thorough mixing.

Fold in the whipped cream, making sure to scrape the bottom of the bowl to incorporate the whipped cream evenly. Spread the mixture into the completely cooled pie shell. Chill for at least 2 hours before serving.

Add chocolate and cream to a small glass measuring cup and microwave for 30 seconds. Stir until the chocolate melts completely and the ganache is smooth. Let cool until it thickens but still pourable, about 2 - 3 hours at room temperature. You can speed up the cooling process by refrigerating the ganache but you’ll need to be careful not to allow it to solidify completely.

Add 1 cup of heavy whipping cream and ¼ cup of powdered sugar to a stand mixer bowl, beat on medium speed. Stream in 1 teaspoon of vanilla and continue beating until stiff peaks.

Spread the whipped cream on top of the pie and drizzle the thickened chocolate ganache over it if using. Alternatively, you can garnish with chocolate curls, cocoa powder, chocolate sprinkles as desired.