Pineapple-Lime Upside Down Cake

Ingredients

• 1 medium lime
• 6 tablespoons (3 oz.) unsalted butter
• 3/4 cup light brown sugar
• 1 fresh pineapple, peeled and cored, cut into 6 (1/4-in.) slices
• 1 1/3 cups (about 5 3/4 oz.) all-purpose flour
• 1 teaspoon lime zest (from 1 lime)
• 1 teaspoon baking powder
• 1/4 teaspoon baking soda
• 1/4 teaspoon table salt
• 2/3 cup light brown sugar
• 1/2 cup (4 oz.) unsalted butter, softened
• 1 large egg
• 1 teaspoon vanilla extract
• 2/3 cup sour cream
• Whipped cream or vanilla bean ice cream