I've made this a few times, and it's always a hit:
3 C all-purpose flour
1 Â½ tsp baking powder
1 Â½ tsp baking soda
1 Â½ tsp salt
Â¾ C unsalted butter, softened
1 ⅔ C granulated sugar
3 large eggs
3 ripe bananas, mashed (about 1 Â¼ C) (best if hand-mashed with a fork)
1 Â½ C buttermilk
1 Â½ C very finely chopped walnuts
4 oz cream cheese, softened
Â½ tsp vanilla extract
Pinch of salt
2 C confectionersâ€™ sugar, sifted
6 oz semisweet-chocolate chips, melted and cooled
1 C very finely chopped walnuts
1 Â½ C unsalted butter, softened
2 (1-lb) boxes confectionersâ€™ sugar, sifted
1 Â¼ Tbsp each vanilla extract, milk
8 drops yellow food coloring
1/4 tsp unsweetened cocoa powder
â€œTomato Sauceâ€ and â€œParmesanâ€
2 (10.25-oz) jars strawberry preserves
Â½ C White chocolate shavings
1. Cake: Preheat oven to 350Â°F. Grease and flour a 13 x 9 x 2â€“in. baking pan. In medium bowl, whisk (by hand) flour, baking powder, baking soda and salt. In large bowl, beat butter until creamy. Add sugar and beat on high until light and fluffy. Add in eggs, one at a time, beating well after each addition. Beat in banana, then buttermilk. On low speed, gradually beat in flour mixture just until incorporated; stir in walnuts. Pour batter into pan, spread as evenly as possible. Bake 50 minutes, or until a toothpick inserted into center tests clean. Cool cake in pan 30 minutes on rack; invert onto rack; let cool. Invert cake onto oval serving platter with flat surface of at least 13 x 9 inches. Cover; refrigerate 3 hours or up to 1 day.
2. Meatballs: In medium bowl, beat cream cheese until creamy and smooth; beat in vanilla and salt. On low, gradually beat in sugar, then chocolate. Stir in nuts. Using 1 Â¾ inch diameter ice cream scoop, scoop chocolate mixture to form about 23 meatballs. Roll each in hands into a ball. Cover; refrigerate (can be made 2 days ahead of time)
3. With thin serrated knife, trim cake to fit platter; cut off edges and corners, cutting downward on diagonal to make oval mound. Remove cake pieces; brush crumbs off platter.
4. Frosting: In large bowl, beat butter until creamy. On low, gradually beat in sugar. Beat in vanilla and milk. Add food coloring and cocoa; beat until color resembles cooked spaghetti. Using offset metal spatula, spread 2 cups frosting in even, thin coat over cake.
5. Spaghetti: Fill 16-in. pastry bag half full with some of remaining frosting and fit with #5 plain tip (1/8 in.). Beginning at bottom edge of cake, pipe â€œspaghettiâ€ strands around sides, looping and overlapping on already piped strands, and working upward. Using up frosting and refilling bag half full as needed, continue piping so strands are densely piped around sides; extend those near top slightly higher than top edge, creating a well.
6. Sauce: In small saucepan, heat preserves over very low heat, stirring, until just barely warm and liquidated (do not overheat). Transfer 1/2 cup â€œsauceâ€ to a small bowl. Spoon remaining sauce into well on top of cake; spread to fill well, letting drips of sauce come over top edge of spaghetti.
7. Put meatballs, a few at a time, in sauce in dish; roll to coat. Transfer to sauce on top of cake. Repeat with remaining meatballs. Brush any remaining sauce from dish over any uncoated meatballs. Either place meatballs on top of cake, or for a more â€œsecureâ€ cake, fasten meatballs into place with toothpicks.
8. Using a vegetable peeler, shave white chocolate â€œParmesanâ€ over top, if desired. (Can be made and refrigerated up to 1 day ahead.) Serve at room temperature.