Day One: Place starter into a large glass or ceramic jar or bowl. Strain peach juice over starter. Cut each peach slice into 4 pieces and add to the starter mixture. Stir in 2 1/2 cups white sugar until combined. Cover loosely with a clean dish towel. Let sit at room temperature for 10 days, stirring once daily. Place the jar in a pan of water to help keep ants away.

Day Ten: Strain pineapple juice over the starter mixture. Cut each pineapple chunk in half and add to the starter mixture. Stir in 1/2 cup white sugar until combined. Cover loosely and let sit at room temperature for 10 days, stirring once daily. The mixture should foam when stirred, and the color will begin to change.

Day Twenty: Cut each maraschino cherry in half and add to the starter mixture. Stir in the remaining 2 1/2 cups white sugar until combined. Cover loosely and let sit at room temperature for 10 days, stirring once daily. The mixture will turn slightly pink from the cherries.

Day Thirty: Drain the liquid from the fruit and divide it among three glass or ceramic pint jars—one for your next cake and two to share with friends. Set the fruit aside.

Preheat the oven to 325 degrees F (165 degrees C). Grease and flour two 9x13-inch baking dishes.

Prepare one cake at a time: Beat 1 package cake mix, 4 eggs, 2/3 cup vegetable oil, and 1 package instant pudding mix together in a large bowl until well combined. Fold in half of the reserved fruit, then stir in 1 cup raisins, 1 cup walnuts, and 1 cup coconut. The batter will be stiff. Spread into one of the prepared baking dishes. Repeat this step with the remaining cake mix, eggs, oil, pudding mix, fruit, raisins, walnuts, and coconut to make the second cake.

Bake the cakes in the preheated oven until a toothpick inserted into the center comes out clean, 55 to 65 minutes.