Step 1: Prepare the Topping

1. Preheat oven to 350°F (175°C).
2. Lightly grease or spray a muffin pan.
3. Pour 1 tsp melted butter and 1 tsp brown sugar into each muffin cup.
4. Place a halved pineapple ring and one cherry in the center of each.

Step 2: Make the Cookie Dough

1. In a large bowl, beat softened butter with granulated and brown sugars until fluffy.
2. Add eggs one at a time, then mix in vanilla and sour cream.
3. In another bowl, whisk flour, baking powder, baking soda, salt, and cornstarch.
4. Gradually incorporate the dry mixture into the wet mixture to form a soft dough.

Step 3: Assemble and Bake

1. Spoon or scoop the cookie dough over the pineapple in each cup, filling almost to the top.
2. Bake for 18–22 minutes, or until golden and set.
3. Let cool for 10 minutes, then carefully invert cookies onto a wire rack.