Prep: 15 min, Cook: 1:30. To prepare gribenes and shmaltz: Render chicken fat by combining first 3 ingredients in a heavy skillet over medium low heat. Cook about 45 minutes. The undissolved bits of fat, skin, and onion should be golden. Strain fat through washed cheesecloth. The gribenes are what remains in the cheesecloth. The rendered liquid is shmaltz. Set aside. Preheat oven to 375°F. Heat 1/4 cup of the reserved shmaltz in a heavy nonstick skillet over medium heat. Saut, diced onions about 10 minutes, until very soft. Increase heat to high and cook 1-2 minutes to lightly brown onions. Meanwhile, cook noodles in a large pot of boiling salted water 7-10 minutes, until tender. Drain. Lightly beat eggs in a large bowl. Stir in noodles and onions. Add reserved gribenes and salt and pepper to taste. Turn the mixture into a 2-quart ovenproof dish that has been lightly greased with 1 Tbs. Shmaltz. Bake 30-40 minutes, until lightly browned on top.