Step 1

Stir together first 4 ingredients. Press mixture evenly into a 9-inch tart pan with removable bottom; set aside.

Step 2

Whisk together sweetened condensed milk, orange juice concentrate, lemon juice, and egg yolks until blended.

Step 3

Beat egg whites at medium speed with an electric mixer until stiff peaks form; fold into condensed milk mixture. Pour into prepared crust.

Step 4

Bake at 325° for 20 to 25 minutes or just until filling is set. Remove to a wire rack, and let cool completely. Cover and chill at least 4 hours. Remove tart from pan, and place on a serving dish.

Step 5

Beat whipping cream and granulated sugar at medium speed with an electric mixer until stiff peaks form. Dollop around edges of tart; garnish, if desired.