Preheat your oven to 350°F (175°C) and line a cupcake pan with 12 cupcake liners.

In a large mixing bowl, whisk together 1 ½ cups of all-purpose flour, 1 cup of granulated sugar, 1 ½ teaspoons of baking powder, and ½ teaspoon of salt.

In another bowl, blend ½ cup of room-temperature milk, 1 large egg, ⅓ cup of vegetable oil, 1 teaspoon of vanilla extract, and 1 cup of mashed overripe banana until smooth.

Pour the wet ingredients into the dry mixture and gently fold them together until just combined.

Spoon the batter into the prepared liners, filling them about three-quarters full, and bake for about 20 minutes.

Remove the pan from the oven and let the cupcakes cool in the pan for 5 minutes before transferring to a wire rack.

In a mixing bowl, whip ½ cup of room-temperature unsalted butter until light and fluffy, then gradually add in the powdered sugar, vanilla extract, and heavy cream until smooth to make the frosting.

For the ganache, combine 1 cup of semisweet chocolate chips and ⅓ cup of heavy cream in a microwave-safe bowl, microwaving until melted and smooth.

Frost each cooled cupcake generously with the vanilla buttercream and allow the frosting to set for about 30 minutes in the refrigerator.

Drizzle the cooled chocolate ganache over the frosted cupcakes, then sprinkle with rainbow sprinkles and top with a maraschino cherry on each.