3 1/2 cups milk1 cup (2 sticks) unsalted butter at room temperature1/2 cup (4 oz) shortening5 1/2 cups sugar1 tablespoon saltZest of 1 lemon15 eggs (at room temperature)5.5 pounds all-purpose flour2/3 cup vegetable oilVegetable shortening for greasing cake pans (approximately 6 teaspoons)3 tablespoons active dry yeast1 tablespoon sugar1 tablespoon flour1 cup warm water1 egg1 tablespoon of water