• Sift together the flour and the salt. Refrigerate for about 10 minutes
• Grate frozen butter, about 1/4 stick at a time, and toss into flour mixture. Repeat until all butter is grated. Refrigerate for about 15 minutes.
• Whisk together the egg, water and vinegar.
• Make a well in the center of the flour and pour in the egg/water mixture. Combine with a fork until just incorporated. It should appear "shaggy".
• Dump it onto a pastry mat and knead a few times to help press it together into a rectangular shape. Wrap in tightly in plastic and chill for an hour in the fridge.
• Cut chilled dough into 12 equal sections and roll into balls. A scale would help, otherwise eyeball them when you are done rolling and the adjust. Chill balls in fridge for another 30 minutes.
• Take out 2 balls from fridge at a time. On a floured surface, flatten ball and roll it into a 5" diameter circle.
• Place one leveled large scoop of filling in each and form it lengthwise in the center. Wet the edges of the circle. Pick up the empanada with one hand and press edges closed with the other. Crimp by starting at one end and fold up and in the sealed edges, appearing almost rope-like. Fold under excess at the end. Place on a rimmed baking sheet lined with foil.
• Brush an egg wash over top and sealed edges. Chill in fridge for another 30 minutes.
• Preheat the oven to 400°F. Bake the chilled empanadas for 25-28 minutes or until golden brown.

Empanada Filling:

• Saute onions in olive oil until softened.
• Add in sausage and cook until crumbled and no longer pink.
• Mix in red pepper flakes and smoked paprika
• Blend in heavy cream. Once combined, add in corn and rice. Remove from heat and allow it to cool.
• Stir grated cheese into cooled mixture. Refrigerate until you are ready to use.