4 or 5 overly ripe bananas (depending on the size), mashed up with one egg and 1/4 cup yogurt and 1/4 cup fat (vegetable oil, olive oil, butter) and 1/2 cup + 2 tbs sugar and 2 tbs molasses (or 3/4 cup brown sugar, but we don't stock it around here; easier to just keep sugar and molasses around). Mix in 2 cups flour, 3/4 teaspoon baking soda and 1/2 teaspoon salt. In my oven, 350 degrees for 40 to 50 minutes (lower if you preheat, higher if you don't bother), until a tester comes clean.
Easy, dense, moist, and not too sweet.
Next up is trying it with applesauce instead of the fat. Then, with carob chips, olive oil for the fat, and coconut. Or maybe crystalized ginger and coconut.