Combine 1 1/4 cups flour and 1/2 teaspoon salt in a medium bowl. Toss the 8 tablespoons cold butter in the flour mixture then using your fingers or a pastry cutter, cut the butter into the flour until it resembles coarse cornmeal with a few larger pieces of butter.

Stir the 1 tablespoon cider vinegar into 1/2 cup of very cold water and drizzle that over the flour mixture. Toss the liquid into the flour by scooping the flour up from the bottom of the bowl with your fingers then letting it fall back down into the bowl through your fingers, pinching it gently here and there until the dough is shaggy and holding together when you squeeze it. Add a tablespoon or two of more water if it is not coming together.

Gather the dough into a ball and wrap in plastic wrap. Refrigerate for at least 30 minutes, preferably an hour. Pie dough can be made up to 3 days in advance. Cover tightly and keep refrigerated until ready to use.

Meanwhile, heat a large frying pan over medium heat. Add the 9 ounces chorizo and 1 large diced sweet potato and cook, stirring occasionally until potatoes are just tender when pierced with a knife, about 10 minutes. Turn heat down if chorizo starts to get too brown. Remove from heat and let cool, slightly.

Heat oven to 350°F and arrange rack in the middle.

On a lightly floured surface, roll crust out to about 1/4-inch thick and about 12-inches in diameter. Transfer dough to a 10-inch tart pan with removable bottom. Press dough into the bottom and up the sides so it fits snuggly. Fold any excess dough over the pan and roll the rolling pin over the edge of the pan, cutting away the dough. Press dough into the sides of the pan, then freeze for 15 minutes. Line dough with a foil or parchment paper, fill with pie weights or beans and place on a baking sheet.

Bake in the middle of the oven for 30 minutes or until dry on the sides. Remove beans, return crust to the oven and continue baking until golden, about another 10 minutes. Remove and let cool slightly.

In a large mixing bowl, whisk together 4 large eggs, 3/4 cup cream, 1/2 teaspoon salt, and 1/4 teaspoon pepper until smooth.

Put chorizo mixture into the bottom of the crust. Top with 2 cups grated cheese and 1/4 cup chopped cilantro and pour the egg mixture over the top.

Bake for 40 minutes or until puffed on the sides and set in the middle. Let cool at least 30 minutes before cutting. Serve warm.