Preheat the oven to 400 º F.

Heat the butter in a 6-quart Dutch oven over medium heat. Add the onions, peppers, celery, garlic, salt, cayenne, and black pepper. Cook, stirring, for 8 minutes or until the vegetables are golden and wilted. Add the flour and cook,  stirring constantly to remove any bits of flour that get stuck to the bottom of the pan, until the roux is golden, usually 6 to 8 minutes. Add the tomatoes and cook for 4 minutes longer.Add the stock and cream, a little at a time, until thick and creamy. Cook for about 5 minutes. Add the crawfish tails and parsley. Stirring occasionally, cook for about 10 minutes. Allow the crawfish to cool for at least 30 minutes.

Allow the dough to come to room temperature. Divide the dough in half and leave half of the dough in the refrigerator. Roll out half of the dough to 1/8-inch thickness and then cut the dough into 4 1/2-inch round circles. Transfer the circles to individual tart shells of the same size. Repeat this process with the other half of the dough and any leftover scraps of dough. You should have 18 individual tarts. Transfer the tart shells to the refrigerator to let the dough rest for at least 15 minutes and up to overnight.

Fill each tart shell with 1/3 cup of the crawfish filling and bake them for 35 minutes or until the edges are brown and the filling is bubbly.

Remove the pies from the oven and let stand for 10 minutes to cool slightly.

Serve the pies on their own or with a side salad.