Start by preparing the filling about 15 minutes ahead so it can cool. In a large bowl, whisk the 12 eggs until runny and no clumps remain.
Heat a 10-inch nonstick skillet over medium-high heat. Add the eggs and cook, stirring frequently with a rubber spatula, for 4 minutes or until just past runny. Do not overcook since eggs will finish cooking in the oven.
Stir the chopped bacon into the cooked eggs. Let the filling cool for 15 minutes.
Preheat oven to 375°F (190°C). Line a half sheet pan with a silicone baking mat or parchment paper.
In a small bowl, whisk the large egg with 1 tablespoon cold water to make an egg wash. Set aside.
On a lightly floured surface, roll out empanada dough discs into 8-inch circles. Place about ¼ cup (60 grams) of cooled filling onto the center of each dough circle. Top with a generous pinch (about 1 ½ tablespoons or 17 grams) of shredded cheddar cheese.
Brush a light glaze of egg wash on one half of each dough circle. Fold the other half over to create a half-moon shape. Press edges together and crimp with fingers or a fork to seal.
Place assembled empanadas on the prepared sheet pan. Brush liberally with egg wash, then use a sharp knife or fork to pierce vent holes on top to prevent bursting during baking. Sprinkle each with a teaspoon of everything bagel seasoning.
Bake for 30-35 minutes until golden brown. Let cool on the baking tray for 2-3 minutes, then transfer to a wire rack to cool for another 5-10 minutes. Serve with fresh fruit, Greek yogurt, and orange juice for a complete breakfast.