Preheat the oven to 400°F (200°C) and line a large baking sheet with parchment paper or a silicone baking mat.
Heat 2 tablespoons of the olive oil in a large skillet over medium heat. Add the ground beef and cook, breaking it up, until browned, about 8–10 minutes. Use a slotted spoon to transfer the beef to a plate, leaving 2 tablespoons of drippings in the skillet.
Add the remaining 1 tablespoon olive oil to the skillet with the reserved drippings. Add the chopped yellow onion and sauté 10–15 minutes until translucent.
Stir in the diced red bell pepper and minced garlic, then add the oregano, kosher salt, chili powder, cumin, and crushed red pepper flakes (if using). Sauté about 3 minutes until the peppers soften and the spices are fragrant.
Pour in 1/4 cup beef broth, scraping up any browned bits from the bottom of the skillet. Stir in 1–2 tablespoons tomato paste (to taste) and cook until the paste dissolves and the mixture is combined.
Return the browned beef to the skillet and add the boiled, finely diced potato and chopped green onions. Stir to combine and remove the filling from heat; let it cool slightly.
Place one dough disc on a work surface. Spoon about 1 1/2 tablespoons of the filling into the center of the disc. Top with a small sprinkle (about 1/2 teaspoon) of chopped scallions and a light sprinkle of shredded Monterey Jack cheese.
Brush the edge of the disc lightly with egg wash, fold the disc over to form a half-moon, and press the edges to seal. Crimp the edges with the back of a fork. Repeat with remaining discs and filling, placing finished empanadas on the prepared baking sheet.
Brush the tops of the empanadas lightly with egg wash and bake in the preheated oven for about 20 minutes, or until golden brown. Serve warm.
