Combine the flour, Parmesan, mascarpone, salt, cayenne and butter in the bowl of a food processor and pulse, pulse, pulse, until it looks very dry and crumbly--what I like to call the Parmesan stage. Add the eggs and pulse until the mixture forms a ball. Remove the dough from the food processor, and refrigerate for at least 30 minutes.
Coat a large saute pan generously with olive oil. Add the garlic and crushed red pepper and bring the pan to a medium heat. When the garlic has become golden brown and is very aromatic remove it and discard, it has fulfilled its garlic destiny. Add the Swiss chard stems, leeks and 2 to 3 tablespoons of water and season with salt. When the water has evaporated and the stems and leeks are soft, add the leaves. Season the leaves with salt and saute until they are very soft and wilted. Remove from the heat and allow the Swiss chard to cool.
In a large bowl combine the ricotta, Parmesan, eggs, cayenne and the Swiss chard mixture. Mix to thoroughly combine. Taste and adjust the seasoning if needed (it will). Set aside.
Preheat the oven to 375 degrees F.
Remove the dough from the refrigerator and let warm up for about 10 to 15 minutes, this will make it really much easier to roll out.
Dust a large clean work surface with flour and roll the dough into a large circle about 1/4 to 1/8-inch thick. Transfer the dough to a large sheet try lined with parchment paper. Lay the dough out flat, don't worry about the overhang on the sides. Put the filling in a large circle in the center of the rolled out dough leaving a 3 to 4-inch border of dough along the outside edge. Fold the dough up around the filling to make a "free-form pie". Brush the top of the dough with egg wash and bake in the preheated oven until the crust is firm, golden brown and shiny, about 45 to 50 minutes. Remove from the oven and let cool for 10 to 15 minutes before slicing, this will allow it to up for easier slicing.