For the topping
1/2 stick (1/4 cup) unsalted butter, melted
2/3 cup firmly packed light brown sugar
3 cups 1-inch chunks fresh pineapple (about 1 pineapple)


For the cake
1 1/2 cups all-purpose flour
1 1/2 teaspoons double-acting baking powder
1/2 teaspoon salt
1/2 teaspoon cinnamon
1 stick (1/2 cup) unsalted butter, softened
2/3 cup granulated sugar
2 large eggs
1 teaspoon vanilla
3/4 cup milk


whipped cream or vanilla ice cream as an accompaniment