Mix together the potatoes, flour, baking powder, 3 eggs, and salt and pepper in a bowl. In another bowl, mix the ground beef, onion, garlic salt, 1 egg, and bread crumbs until well-combined.
Heat the oil in a skillet over medium-low heat, and drop a rounded tablespoon of potato mixture into the hot skillet. Spread and flatten the pancake out a little, and place about 2 teaspoons of beef mixture on the pancake, spreading the filling out almost to the edges of the pancake. Drop another rounded tablespoon of potato mixture on top of the beef, and spread it out to completely cover the beef. Fry until the bottom of the pancake is golden brown, about 5 minutes, then flip and fry the other side until golden, 1 to 2 more minutes.