1. Preheat oven to 350°F. Grease and flour two 8- or 9-inch round cake pans.
2. Prepare, bake and cool cake following package directions for basic recipe. Chill layers for ease in splitting.
3. Place cream cheese, sugar and vanilla extract in small bowl. Beat at low speed with electric mixer until smooth. Add pecans; stir until blended. Set aside. Beat whipping cream in small bowl until stiff peaks form. Fold whipped cream into cream cheese mixture.
4. To assemble, split each cake layer in half horizontally (see Tip). Place one cake layer on serving plate. Spread top with one fourth of filling. Repeat with remaining layers and filling. Garnish with strawberry halves and mint leaves, if desired. Refrigerate until ready to serve.
Tip
To split layers evenly, measure cake with ruler. Divide into 2 equal layers. Mark with toothpicks. Cut through layers with serrated knife, using toothpicks as guide.