Preparation Preheat oven to 350°F. Butter and flour four 5 3/8 x 3 1/4 x 1 7/8-inch loaf pans. Sift flour, baking powder and salt into medium bowl. Using electric mixer, beat sugar and unsalted butter in large bowl until light and fluffy. Add eggs 1 at a time, beating well after each addition. Beat in orange juice, grated orange peel and vanilla extract (batter may look curdled). Beat in flour mixture. Fold in poppy seeds. Divide batter equally among prepared pans (about 1 1/2 cups each). Place pans in oven. Bake until tops of cakes are brown and tester inserted into center comes out clean, about 55 minutes. Transfer pans to rack. Cool cakes 10 minutes. Cut around sides of pans to loosen cakes. Turn cakes out onto wire racks and cool completely. (Cakes can be prepared up to 1 week ahead. Wrap in aluminum foil; store cakes at room temperature.)
Preparation Preheat oven to 350°F. Butter and flour four 5 3/8 x 3 1/4 x 1 7/8-inch loaf pans. Sift flour, baking powder and salt into medium bowl. Using electric mixer, beat sugar and unsalted butter in large bowl until light and fluffy. Add eggs 1 at a time, beating well after each addition. Beat in orange juice, grated orange peel and vanilla extract (batter may look curdled). Beat in flour mixture. Fold in poppy seeds. Divide batter equally among prepared pans (about 1 1/2 cups each). Place pans in oven. Bake until tops of cakes are brown and tester inserted into center comes out clean, about 55 minutes. Transfer pans to rack. Cool cakes 10 minutes. Cut around sides of pans to loosen cakes. Turn cakes out onto wire racks and cool completely. (Cakes can be prepared up to 1 week ahead. Wrap in aluminum foil; store cakes at room temperature.)