In a large bowl, cream butter and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition. Add extracts. Combine the flour, baking powder and salt; gradually add to creamed mixture alternately with eggnog, beating well after each addition. Pour into two 9-in. round baking pans coated with cooking spray. Bake at 350° for 30-35 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing to wire racks to cool completely. In a small saucepan, combine flour and salt. Gradually stir in eggnog until smooth. Bring to a boil over medium heat; cook and stir for 2 minutes or until thickened. Cool to room temperature. For frosting, in a large bowl, cream butter and sugar until light and fluffy. Beat in eggnog mixture and vanilla until smooth. Remove 1/4 cup frosting for decorating if desired; tint 3 tablespoons green and 1 tablespoon red. Spread plain frosting between layers and over top and sides of cake. Use green and red frosting to pipe leaves and berries on cake. Store in the refrigerator.