Puerto Rican Pineapple Rum Cake

INGREDIENTS

• 1/2 cup packed light brown sugar
• 1 1/2 cups dark rum
• 1/4 cup unsalted butter
• 1/2 pineapple, cored and cut into 1/4-inch-thick slices
• 1 cup unsalted butter
• 2 cups sugar
• 4 large eggs
• 1 teaspoon pure vanilla extract
• 1 teaspoon dark rum
• 2 1/2 cups all-purpose flour
• 1/2 teaspoon kosher salt
• 1/2 cup crushed pecans
• vanilla ice cream, for serving