I'm pleased to report my hodgepodge cake did so well that the recipe was requested more than once. I mixed the sugar-free vanilla pudding and cool whip together to create a bit of stability for the icing, and threw in more blueberries during layering for a bit of a surprise. If you have a cake saw, this would be a good time to use it to level out the bottoms on the cake. This way, you don't get slip sliding layers all over.
I chose plums that were firm but ripe, and sliced them uniformly for the best results. I would also recommend refrigerating this cake so it keeps its form. Also, cut it with a sharp knife so you can preserve the fruit pattern on top.
Plum Blueberry Summer Cake Recipe
3 plums, pitted and thinly sliced
1 box yellow cake mix (and the ingredients to make it)
2 tablespoons butter
1/4 cup brown sugar
1 16-ounce tub of cool whip
1 package of sugar-free vanilla pudding
Start by preheating the oven to 350. Place the butter and sugar in the bottom of a 9-inch cake round and place in the oven until melted and bubbly. Meanwhile, make the yellow cake according to the instructions.
Remove from the oven and arrange the plums, then layer blueberries across the plums. Gently spoon the cake batter over the plums, then divide the rest of the batter into another greased 9-inch cake pan. Bake both pans for 35 minutes or until cooked.
Remove pans from the oven and allow to cool completely. Level the cakes with a cake saw or a sharp knife. Mix the cool whip and the pudding together. Place the not-plum cake layer on a cake stand first, then top with 1/3 of the cool whip mixture. Level and add berries or more plums or both, then place the plum cake on top. Use the remaining cool whip to "ice" the cake. I found it easiest to put a thin layer on, then refrigerate it for 20 minutes before placing the remaining mixture on it. Cover and refrigerate until consuming. This cake just gets better over time, and I would say you have three days to eat it while it's still awesome.