Preheat your oven to 350°F (175°C) and lightly grease a 12-cup muffin pan.
Pour the melted butter evenly into the bottom of each muffin cup (about 1 teaspoon per cup). Sprinkle brown sugar on top of the butter in each cup.
Place a halved maraschino cherry in the center of each muffin cup, cut side up. Arrange a few pineapple chunks (or a spoonful of crushed pineapple) around the cherry to cover the bottom.
In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, baking soda, and salt.
In a separate bowl, mix together the milk, vegetable oil, vanilla extract, and egg until smooth.
Pour the wet ingredients into the dry ingredients, stirring just until the batter is combined. Avoid overmixing for the softest cupcakes.
Spoon the batter over the fruit in each muffin cup, filling them about 2/3 full.
Bake for 20-25 minutes, or until the tops are golden and a toothpick inserted into the center comes out clean.
Allow the cupcakes to cool in the pan for about 5 minutes. Then, run a knife around each cupcake, place a baking sheet or wire rack on top of the pan, and carefully invert to release the cupcakes with the pineapple side up.
Serve warm for a gooey, comforting treat—or let them cool completely for an easy-to-pack snack!
Notes
Store in an airtight container at room temperature for up to two days, or refrigerate for up to four days. These cupcakes freeze well for up to two months.