Pineapple Upside-Down Donuts

For the batter:

• 1 cup all-purpose flour 2 tablespoons
• 1/2 cup light brown sugar packed
• 1/2 teaspoon salt
• 1 teaspoon baking powder
• 1/2 teaspoon cinnamon
• 1/4 cup milk vanilla almond milk or cow's milk alternative
• 1/4 cup pineapple juice unsweetened
• 1 teaspoon vanilla extract
• 2 1/2 tablespoons unsalted butter melted
• 1 egg large, at room temperature

For the pineapples:

• 6 lices pineapple from a can, patted dry, sliced in half
• 6 tablespoons dark brown sugar