Let egg whites stand at room temperature for 30 minutes.
In a large bowl, combine the cake mix, orange juice, egg yolks and orange zest; beat on low speed for 30 seconds. Beat on medium for 2 minutes. Pour into two greased and floured 9-in. round baking pans; set aside.
In a large bowl with clean beaters, beat egg whites and cream of tartar on medium until soft peaks form. Gradually beat in 1 cup sugar, a tablespoon at a time, on high until stiff glossy peaks form. Spread the meringue evenly over cake batter.
Bake at 350° for 35 minutes or until meringue is lightly browned. Cool in pans on wire racks (meringue will crack).
Meanwhile, in a large bowl, beat cream until stiff peaks form. Mash 1/2 cup of strawberries with remaining sugar; fold into whipped cream.
Loosen edges of cakes from pans with a knife. Using two large spatulas, carefully remove one cake to a serving platter, meringue side up. Carefully spread with about two-thirds of the cream mixture. Slice the remaining berries; arrange half over cream mixture. Repeat layers. Store in the refrigerator.