First Birthday Banana Sour Cream Cake

1 pkg. (2-layer size) yellow cake mix
3 eggs
1 cup mashed ripe bananas (about 3)
1 cup sour cream
1/4 cup oil

1 pkg. (8 oz.) cream cheese , softened (full fat or reduced fat)
1/2 cup (1 stick) butter, softened
1 pkg. (16 oz.) powdered sugar
1 cup finely chopped walnuts**

Oven at 350°F. Beat first 5 ingredients with mixer on low speed just until moistened, stopping frequently to scrape bottom and side of bowl. Beat on medium speed 2 min. Pour into greased and floured 13x9-inch pan. (Or you may choose to use 2 9-inch circle pans) Bake 35 min. or until toothpick inserted in center comes out clean. (If using circle pans, follow cooking time on box.) Cool completely.

Beat cream cheese and butter with mixer until well blended. Gradually add sugar, beating well after each addition.

Remove cake from pan. Carefully cut cake crosswise in half using serrated knife. Place 1 cake half, top-side down, on plate; spread with some of the cream cheese frosting. Top with remaining cake half, top-side up. Spread top and sides with remaining frosting. Press nuts into sides. Keep refrigerated. (If using circle pans, frost traditionally, using nuts if wanted).

**Note-Since this was a first birthday cake for my son, we omitted the nuts.
**Note-I made this for two separate birthday parties and both time got rave reviews!