Heat oven to 350°F. Spray 2 (9x2-inch) round baking pans with cooking spray. Line bottom of pans with parchment paper; spray paper.
Combine milk and orange juice in small bowl.
Whisk flour, baking powder and salt in medium bowl.
Mix butter and 2 cups sugar in large bowl at medium speed 2 minutes or until smooth and creamy.
Add eggs one at a time, beating well after each addition.
Add in 2 teaspoons vanilla.
Beating slowly, beat in flour mixture in 3 parts alternately with orange juice mixture, beginning and ending with flour mixture. Divide batter between pans.
Bake for 30- 35 minutes or until toothpick inserted in center comes out clean. Cool in pans on wire rack 15 minutes.
Remove cakes from pan and remove parchment. Turn cakes top-side up; cool completely.
(Cake can be made 1 day ahead. Cover and store at room temperature.)
7 Minute Frosting
Beat 1 1/4 cups of the sugar, water, egg whites and cream of tartar in large heatproof bowl at high speed 1 minute or until egg whites are foamy and opaque. Place bowl over saucepan of barely simmering water (bowl should not touch water); beat at high speed 7 minutes or until soft peaks form
Remove bowl from saucepan. Add orange peel and 1 teaspoon vanilla; beat at high speed 2 minutes or until slightly cool and thickened.
Combine sliced strawberries and remaining 1 tablespoon sugar in large bowl; let stand 15 minutes.
Slice cake layers in half horizontally. Spoon one-third of the strawberry mixture, including juice, over bottom layer; top with second layer and one-third strawberry mixture. Spread 1 cup of the frosting over strawberry mixture; top with third layer and remaining strawberry mixture. Top with fourth layer.
Spread remaining frosting over sides and top of cake, swirling to decorate.