Mango upside down cake

First iteration making up a recipe: it came out alright, not terrific yet. This is a small portion.
Prepare a muffin pan by greasing the cups with butter. Could be baked in a loaf pan as well.
Preheat oven to 375 F.

• 1 pound mangos (about five small) - peel and cut into chunks or scoop pulp if very soft.
• Melt 1/2 cup butter over heat until just melted. Will use as 1/6 cup and 1/3 cup separately.
• Separate mango chunks from pulp (about half and half) and put in saucepan with 1/6 cup butter, 1/3 cup turbinado cane sugar, and 3 Tbsp rum. Simmer over low heat ten minutes.
• Spoon mango chunks into the bottom of each cup or pan as upside-down topping.
• Optional: sprinkle some Anahola Granola over the mango chunks.
  
• Sift together 1 cup whole wheat flour, 2 tsp baking powder, and 1/2 tsp salt.
• Beat 2 eggs into the remaining 1/3 cup melted butter, 1/3 cup turbinado cane sugar, 2 tsp vanilla, and the remaining mango pulp and chunks.
• Fold the flour mixture into the liquid without over stirring.
• Spoon batter on top of the mango chunks.

Bake 25 minutes for muffin pan until done (toothpick test). Let sit then remove from pan while warm.
The amount of mango is variable so adjust the batter to a thick pancake batter consistency by adding flour to thicken or add yogurt to thin.
Caveat: I prepared this with the minimal kitchen here, specifically, no measuring utensils.

I have located a mango tree that drops ripe fruit onto the public roadway there for taking which is great for experimenting with this recipe as mango are expensive in the market.